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Gender differences during heat strain at ctitical WBGT

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Gender differences during heat strain at ctitical WBGT
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Luecke, Christina L
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Heat stress
Heat strain
Heat balance
Gender
Physiological responses to heat
Occupational heat exposure
Dissertations, Academic -- Public Health -- Doctoral -- USF
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bibliography   ( marcgt )
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ABSTRACT: Heat stress is influenced by environmental conditions, workload and clothing. A critical environment is the upper limit of compensable heat stress for a given metabolic rate and clothing ensemble. The physiological strains associated with heat stress are core and skin temperatures, heart rate and physiological strain index (psi). Because heat dissipation mechanisms may differ between men and women, there may be gender differences in the critical environment and the associated physiological variables. Gender differences were explored between acclimated men (n = 20) and women (n = 9) at the upper limit of compensable heat stress. Participants walked on a motorized treadmill at a target metabolic rate of 160W/m2 while wearing five different clothing ensembles (cotton work clothes, cotton coveralls, and three coveralls of particle barrier, liquid barrier, and vapor barrier properties). The starting air temperature (Tdb) was 34°C and humidity was held constant at 50%. Once thermal equilibrium was achieved, Tdb was increased 1°C every five minutes until loss of thermal equilibrium or termination criteria were met. Upon initial analysis, several gender differences were found. A significant difference (p = 0.035) was found for WBGTcrit, where values were 32.5°C for men and 33.1°C for women. Women had higher average heart rates (hr = 125 and 112 bpm), average skin temperatures (Tsk =36.4 and 36.2°C), and psi values (4.5 and 3.8) than men. No significant difference was found between genders for core temperature (tre) (p = 0.147). The target metabolic rate of 160W/m2 was not achieved and there were significant differences (p < 0.0001) between men (172 W/m2) and women (152 W/m2). The effects of metabolic rate on WBGTcrit was examined and it was discovered that the difference in WGBTcrit could be explained by the difference in metabolic rate. The same logic was applied to the physiological responses and confirmed a difference betweengenders for Tre, HR, and PSI . The differences for Tsk disappeared. These findings indicate that women experienced a greater cardiovascular strain at the critical conditon and also greater heat strain than men at the same heat load.
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Dissertation (Ph.D.)--University of South Florida, 2006.
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Includes bibliographical references.
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by Christina L. Luecke.
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Gender Differences During Heat Strain at Critical WBGT by Christina L. Luecke A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Environmental and Occupational Health College of Public Health University of South Florida Major Professor: Candi D. Ashley, Ph.D. Thomas E. Bernard, Ph.D. Steve Mlynarek, Ph.D. Skai Schwartz, Ph.D. Date of Approval: June 2, 2006 Keywords: heat stress, heat st rain, heat balance, gender, ph ysiological responses to heat, occupational heat exposure Copyright 2006, Christina L. Luecke

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ACKNOWLEDGEMENTS I would like to acknowledge the National Institute for Occupational Safety and Health for providing the traineeship that enab led me to pursue my doctoral education. I would also like to thank them equally fo r the funding of the research itself. Thank you to Allison Kaehler, Bunmi Oladin ni, Veekash Nana, and all of the lab staff who helped over the whole three year s. I would also like to acknowledge my committee for their patience and mentoring th roughout my studies. Dr. Ashley and Dr. Bernard provided continuous support along wi th knowledge and experience that were invaluable. In addition, I w ould like to thank OHC Envir onmental Engineering for its support. Finally, I want to thank my family for their unending confidence in me and in my endeavor. They were my inspiration.

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i TABLE OF CONTENTS LIST OF TABLES.............................................................................................................iii LIST OF FIGURES...........................................................................................................iv ABSTRACT....................................................................................................................... .v INTRODUCTION..............................................................................................................1 LITERATURE REVIEW...................................................................................................3 Critical Heat Stress Condition................................................................................3 Metabolic Rate........................................................................................................4 Clothing...................................................................................................................5 Personal Factors......................................................................................................6 Fitness.........................................................................................................8 Gender.........................................................................................................9 Physiological Response and Gender.....................................................................10 Skin Temperature......................................................................................10 Sweat Rate................................................................................................11 Heart Rate.................................................................................................12 Core Temperature.....................................................................................14 Physiological Strain Index........................................................................14 Hypothesis.............................................................................................................15 METHODS.......................................................................................................................1 7 Participants............................................................................................................17 Clothing.................................................................................................................18 Equipment.............................................................................................................19 Protocols...............................................................................................................20 Acclimation...............................................................................................20 Experimental Sessions..............................................................................20 Critical Conditions................................................................................................21 Statistical Analysis................................................................................................21 RESULTS........................................................................................................................ .23 Level of Heat Stress..............................................................................................23 Heat Strain............................................................................................................25 Effect of Metabolic Rate.......................................................................................29

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ii DISCUSSION...................................................................................................................32 Level of Heat Stress..............................................................................................32 Heat Strain at WBGTcrit........................................................................................33 Effects of Metabolic Rate.....................................................................................35 Conclusion............................................................................................................37 REFERENCES.................................................................................................................39 APPENDIX A...................................................................................................................44 APPENDIX B...................................................................................................................47 APPENDIX C...................................................................................................................64 ABOUT THE AUTHOR.......................................................................................End Page

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iii LIST OF TABLES Table 1. Summary of Part icipant Characteristics...........................................................18 Table 2. Summary of Sub-Study Participant Characteristics.........................................18 Table 3. Means and Standard De viations of Metabolic Rate.........................................24 Table 4. Critical WBGT (WBGTcrit C) for Men, Women, and Both Wearing All Ensembles........................................................................................................24 Table 5. Core Temperature (Tre C) Means and Standard Deviations at the Critical Condition for Men, Women, and Both Wearing All Ensembles.....................25 Table 6. Heart Rate (HR) Means and Standard Deviations at the Critical Condition for Men, Women, and Both Wearing All Ensembles......................................26 Table 7. Skin Temperature (Tsk C) at the Critical Condition for Men, Women, and Both Wearing All Ensembles...........................................................................27 Table 8. PSI at the Critical Condition for Men, Women, and Both Wearing All Ensembles........................................................................................................28 Table 9. Summary of Differences Be tween Gender and Among Ensembles for Physiological Responses..................................................................................29 Table 10. Relationship to WBGTcrit and Physiological Responses to Normalized Metabolic Rate (MSA).....................................................................................30 Table 11. Adjusted Values of WBGTcrit and Physiological Responses Based on the Difference in MSA...........................................................................................31

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iv LIST OF FIGURES Figure 1. Comparison of WBGTcrit for Men and Women in All Ensembles..................25 Figure 2. Comparison of Tre at WBGTcrit for Men and Women in All Ensembles.........26 Figure 3. Comparison of HR at WBGTcrit for Men and Women in All Ensembles........27 Figure 4. Comparison of Tsk at WBGTcrit for Men and Women in All Ensembles.........28 Figure 5. Comparison of PSI at WBGTcrit for Men and Women in All Ensembles........29

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v Gender Differences During Heat Strain at WBGTcrit Christina L. Luecke ABSTRACT Heat stress is influenced by environmen tal conditions, workload and clothing. A critical environment is the upper limit of compensable heat stress for a given metabolic rate and clothing ensemble. Th e physiological strains associated with heat stress are core and skin temperatures, heart rate and Physio logical Strain Index (PSI). Because heat dissipation mechanisms may differ between men and women, there may be gender differences in the critical environment and the associated phys iological variables. Gender differences were explored between acclimated men (n = 20) and women (n = 9) at the upper limit of compensable heat stress. Partic ipants walked on a motorized treadmill at a target metabolic rate of 160W/m2 while wearing five different clothing ensembles (cotton work clothes, cotton coveralls, and three cove ralls of particle barri er, liquid barrier, and vapor barrier properties). The starting air temperature (Tdb) was 34C and humidity was held constant at 50%. Once thermal equilibrium was achieved, Tdb was increased 1C every five minutes until loss of thermal equilib rium or termination criteria were met. Upon initial analysis, several gender differen ces were found. A signi ficant difference (p = 0.035) was found for WBGTcrit, where values were 32.5 C for men and 33.1C for women. Women had higher average heart ra tes (HR = 125 and 112 bpm), average skin temperatures (Tsk =36.4 and 36.2C), and PSI values (4.5 and 3.8) than men. No

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vi significant difference was found between genders for core temperature (Tre) (p = 0.147). The target metabolic rate of 160W/m2 was not achieved and there were significant differences (p<0.0001) between men (172 W/m2) and women (152 W/m2). The effect of metabolic rate on WBGTcrit was examined and it was discovered that the difference in WBGTcrit could be explained by the difference in metabolic rate. The same logic was applied to the physiological responses and confirmed a difference between genders for Tre, HR, and PSI. The differences for Tsk disappeared. These findings indicate that women experienced a greater cardiovascular strain at the critical condition and also greater heat strain than men at the same heat load.

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1 INTRODUCTION Heat stress is influenced by work de mands, environment, and clothing. To maintain thermal equilibrium, heat gains from the metabolic demands and the environment are balanced by the evaporative he at loss plus any loss due to convection or radiation. The maximum rate of evaporative heat loss is modified by the ability of the clothing to support water vapor transport and by the water vapor in the air. The greater the heat gain the greater the evaporative cooling must be to maintain equilibrium. When the person is able to maintain thermal equilib rium, the heat stress condition is considered compensable. When equilibrium cannot be maintained because the gains exceed the capacity to dissipate the heat, then th e heat stress is called uncompensable. Generally, physiological responses to heat stress include increased heart rate, skin temperatures, sweat rate, and core temperatur e. Personal factors such as acclimation state, fitness level, and gender affect an individual’s response to heat stress. Acclimation to the heat induces physiological adaptations to improve heat tolerance. The adaptations include increased sweat rate, d ecreased heart rate, and increas ed plasma volume. Fitness level also improves the response to heat stress as long term aerobic tr aining leads to many of the same adaptations as acclimation. Prior research demonstrates differences in physiological response to heat stress between the genders. Th ese differences appear in studies that do not select men and women based on matching cr iteria; and they tend to be minimized if participants are acclimated and matched on maximum aerobic capacity.

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2 Occupational exposure limits are based on th e level of heat stress at the critical condition, or the transition point between comp ensable and uncompensable heat stress. Given that there are average differences in physiological responses of men and women toheat stress, it may be reasonable to suspect that critical conditions would be different. If there are no differences in the transition between compensable and uncompensable heat stress for men and women, then there may be a difference in the physiological cost at the upper limit of compensable heat stress. In su mmary, it is not known if exposure limits to heat stress may be influenced by gender. Fu rther, the physiological cost of working at that limit might be differe nt for men and women.

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3 LITERATURE REVIEW Heat stress assessment follows traditi onal industrial hygiene exposure assessment methods such as the Threshold Limit Value (TLV)(1). The exposure assessment is commonly accomplished by setting a wet bulb globe temperature (WBGT) limit based on the work demands and clothing requirements. Heat strain is the collective physiological response to heat stress, and repr esents the individual cost of the heat stress exposure. The underlying assumption of using heat stress exposure limits is th at the heat strain is then managed. Critical Heat Stress Condition WBGT-based exposure assessment has its roots in the work of Lind (2) in 1963, when he proposed the Upper Limit of the Pr escriptive Zone (ULPZ). Fundamentally, the ULPZ is the critical conditions or the uppe r bound on compensable heat stress. Lind's ULPZ forms the basis for the NIOSH Recommended Exposure Limit (REL) (3) and the ACGIH TLV for heat stress and strain (1). Belding and Kamon (4), Kenney, Mikita, Havenith, Puhl, and Crosby (5), and Barker, Kini, and Bernard (6) have developed progressive heat stre ss exposure protocols that shorten the time needed to identify the critical conditions or the upper bound on compensable heat stress. While not used to set occupational exposure limits, these protocols have been used to examine the e ffects of humidity, air speed, and clothing on

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4 the critical conditions and to explore differences in physiological responses for acclimation, gender and fitness as described later. Metabolic Rate Because the level of heat stress and the level of physiological strain depend on the metabolic rate, it is worthwhile mentioning so me of the interactions For any individual in a thermally neutral environment, steady-stat e core temperature and heart rate increases with the metabolic rate. To make comparis ons of core temperature and heart rate among individuals, it is customary to make those co mparisons with reference to aerobic capacity. That is, as a first approximation, the core te mperature and heart rate is the same across individuals working at the sa me fraction of their maximum aerobic capacity. Below the critical conditions of heat stress for the indivi dual, the core temperatur e is not expected to change, and will be that of the thermally neutral conditions. Th e heart rate is expected to be elevated to accommodate the added blood flow to the skin as the critical condition is approached. On the other hand, level of heat stress depends on the actual metabolic rate, because it represents the rate of heat generation that must be removed to maintain thermal equilibrium. Because the heat exchange surface is nominally the body surface area, there is a convention to report metabolic rate ad justed to body surface area, or normalized metabolic rate. As the normalized metabolic rate increases, the environmental conditions must be come more favorable to heat lo ss by evaporation, which means the absolute humidity is lower or the WBGT is lower. For heat stress exposure assessment, the ISO (7) method uses normalized metabolic rate while the NIOSH (3) and ACGIH (1)

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5 recommend absolute metabolic rate. In either case, the level of heat stress is expressed as the combination environmental conditions (e.g., WBGT) and metabolic rate, without reference to fitness. This interaction of metabolic rate with heat stress and physiological response leads to a quandary that re quires a careful statement of the research question. For instance, if the central resear ch question is physiol ogical response to he at stress due to gender, then both the heat st ress level and relative metabolic demands must be matched simultaneously. This is accomplished by ma tching the participan ts by aerobic capacity and the setting the metabolic rate as a per cent of the capacity at a fixed environmental condition. Recognizing that th ere are differences in the population of men and women for aerobic capacity, this masks the population eff ects (8). If the absolute metabolic rates are not used, then the level of heat stress is matched but the core temperatures and heart rates may be biased high for women who ha ve a lower average aerobic capacity. Clothing Clothing provides a barrier against harmfu l chemical and physical agents, but in turn, can hinder heat dissipation. When unc lothed, thermal exchange can occur directly across the skin. When clothed, an air layer or microenvironment is formed between the skin and the environment. When multip le layers of clothing are worn, multiple microenvironments are formed between the la yers. Metabolically generated heat must pass through each microenvironment before be ing dissipated to the ambient environment (9). For this reason, thermal properties of di fferent clothing ensembles such as insulation, ventilation, and permeability greatly influen ce heat dissipation from the skin to the

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6 environment. For example, water barr ier and vapor barrier clothing decrease permeability, hindering evaporative heat loss (10). Progressive heat stress protocols are used to evaluate the total insulation and th e total evaporative resistance of clothing ensembles (6,11,12). In addition, this protocol is used to recommend clothing adjustment factors by comparing the mean critical conditions for work clothes to the mean critical conditions for the clothing ensemble of inte rest. Numerous studi es reported clothing adjustment vapor barrier clothing at a value of around 9 to 11C (11,12,13,14). In contrast, cotton work clothes or coveralls ha ve a much lower adjustment factor ranging from 0 to 4C; other types of clothing to be considered include water barrier, vaportransmitting ensembles (0 to 5.5C) and partic le barrier ensembles (1.5 to 2.0C) (10). Also, the layering of any combination of fabr ics or ensembles increases the effects of heat stress (10). Personal Factors External influences of heat stress include environment, clothing, and MR. Interpersonal differences in re sponse to heat stress may be attributed to acclimation status, cardiovascular fi tness, and gender. Acclimation Acclimatization is repeated exposure to heat, which induces physiological adaptations to improve heat tolerance. Wh en this improved tolerance is achieved by exercise in a controlled environmental chambe r, it is called acclimation. For the purposes of this paper, the effects of heat acclim ation and acclimatization are similar and the process will be referred to as acclimation.

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7 Physiological effects of acclim ation include decreased HR (15,16,17,18,19,20,26,28,31,33,36), decreased Tre (15,16,17,19,26,28,33,36), decreased Tsk (15,16,20,26,31,33,36), and lower Tre at the onset of sweating (21,22,26,36). There is also increased plasma volume (21,22,23,24,25,26,31,36) reduced sodium chloride in sweat (27,31), and increased sweat ra te (15,16,17,18,19,20,31). Pandolf (28) and Cheung (15) reported decreased ratings of perceived exertion and th ermal sensation as well. The development of acclimation occurs by exposing workers to a hot environment for increasing time. Traditional acclimation protocols use low exercise intensities (4060% VO2max) for 1-2 hours per day over 6-10 days (28,29,30). Hot-dry and hot-wet environments are equally sufficient to i nduce physiological changes of improved heat tolerance (16,28,31,32). Gill and Sleivert (33) studied the differences in acclimation of daily versus intermittent exposure to heat. Fourteen competitive rowers were randomly assigned to either an intermittent (10 sessions over 3 weeks) or a consecutive (10 days) acclimation group. They found that Tre decreased significantly with intermittent exposure, but found a significantly larger decrease with c onsecutive day heat exposure. HR, Tsk, and ratings of perceived exertion also d ecreased significantly with consecutive a cclimation, but not with intermittent acclimation. The investigat ors concluded that some adaptation occurs with intermittent heat exposure, but daily he at exposure is a more effective acclimation strategy. The changes induced by acclimation devel op quickly over the first few days and are essentially complete after two weeks. Acc limation is said to be complete when there

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8 is a plateau in the physiological adap tations including decreased HR and Tre and increased SR (34). HR and plasma volume ad aptations occur in the first few days, while Tre and sweating adjustments take place after ab out six days of acclimation (23). As HR can be affected by other va riables unrelated to thermal load, an increase in Tre is a better predictor of exhaustion from heat stress (32). For this reas on, a plateau in Tre is most often used as the major criteria for complete acclimation (16). Fitness Habitual exercise or long-term aerobi c training leads to similar physical adaptations as acclimation especi ally in cardiovascular efficiency (15). Plasma volume increases by about 20%, which leads to an increase in stroke volume, due to greater venous return and a greater end diastolic volu me. The increase in stroke volume results in a reduced HR and an increase in muscle blood flow (35). In addition, there is an enhanced sweating response at a given percentage of maximal effort. Overall, there is a decrease in physiological strain and energy cost for a given submaximal workload (36). Aerobic capacity is expressed as maximal oxygen uptake (VO2max). The average for women is 2.0L/min and 3.5L/min for men. When adjusted for body weight, VO2max is 33 and 40ml/kg respectively (23,37). In indus trial settings, men a nd women generally do similar jobs. As men have a higher VO2max, women work at a higher percentage of aerobic capacity than men in general. As a result, women have higher HRs, higher body temperatures, greater perceived stress, and quick er onset of fatigue during exercise (8).

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9 Gender Generally it is believed that women are at a disadvantage in hot environments. First, women have a smaller muscle mass to fat ratio, which leads to less efficient work and more heat production. Next, a smaller bl ood volume coupled with a larger surface area-to-mass ratio leads to a gr eater effect of dehydration. Sweat initiation occurs at a higher Tre and Tsk causing more heat storage at sweat onset. Also, Tsk is usually higher in women in hot environments because they rely more on convective heat loss, allowing less heat conductance (38). Women have a lowe r SR than men of equal fitness, size, and acclimation state. This may be a disadvant age in hot dry environments where men can dissipate more heat through evaporative cooling (39). However, in hot-wet environments women may be at an advantage as they depend more on convective rather than evaporative he at loss (39). Shapiro, Pandolf, Avellini, Pimental, and Goldman (40) studied 10 men and 9 women after acclimation in hot wet, hot dry, and comfortable environments. Duri ng the hot wet protocols, women had lower Tsk, Tre, and less sweat loss. Here a larger surface area to mass ratio led to more evaporative heat loss. The oppos ite was true in the hot-dry e xperiments. Men were at a physiological advantage producing lower Tre and Tsk, lower HR, and lower heat storage. Men and women tended to react similarly in the comfortable environments, indicating that the physiological advantag es/disadvantages were relate d to the type of climate, specifically whether it was wet or dry. Gender differences in physiological res ponse to heat stress may be reduced if fitness level, and acclimation state are sta ndardized (38,39). Paolone, Wells, and Gerard

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10 (41) found physically fit women were capable of working in the heat about as well as men when workload is relative to individual maximal capacities. Physiological Response and Gender General physiological responses to heat stress include an increase in HR, SR, and Tre. There is also an increase in Tsk due to increased periphe ral blood flow. Conflicting evidence exists regarding gender differences in physiological responses to exercise. In addition to examining these physiological res ponses, a physiological strain index (PSI) can be used as a tool to evaluate heat stress. Skin Temperature Most studies found no difference in Tsk between genders when matched on fitness (41, 42,43,44, 45,46,51). However, a few found that women tended to have higher Tsk than men when participants were not matche d on fitness (47,45) or during exercise in hot dry environments (40,48). Moran, Shapiro, La or, Izraeli, and Pandolf (45) looked at three groups of acclimated participants. The first two groups were of similar fitness and included nine women and eight men with maximal aerobic capacities of 46.1 and 43.6 ml/kg, respectively. The third group consisted of eight men who were significantly more fit (P<0.0001) than the first two groups with maximal aerobi c capacity of 59.1 ml/kg. All groups worked at an equivalent workload. Each completed nine trials in comfortable, hot wet, and hot dry environments at low, modera te, and high exercise in tensities. There was no difference in Tsk when men and women were matche d on fitness, but a significant difference (p<0.005) was found when comparing fit men to women. McLellan (47) also found a higher average Tsk for women than men (0.1-0.2 C) while performing light

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11 intermittent exercise at equivalent absolute metabolic rate. These participants were not matched on fitness and were not acclimated. Yousef, Dill, Vitez, Hillyard, and Goldma n (48) and Shapiro et al. (40) both found women to have higher Tsk in hot dry environments. Y ousef et al. (48) studied 57 men and 60 women all between the ages of 17 and 31 walking for three one-hour trials in desert heat at 40% of VO2max. Women had a signi ficantly higher average Tsk than men (p<0.05). Shapiro et al. (40) examined 9 women and 10 men under hot wet, mild wet, and hot dry conditions. Tsk for women was higher in the hot dry conditions but lower in the hot wet conditions. Men rely more on ev aporative heat loss and women rely more on convective heat loss. Using this reasoni ng, it is not surprising that men had higher Tsk in mild wet and hot wet conditions. Sweat Rate Most studies report a higher sweat rate (SR) in men (42,40,41,44,46,47,48, 49,50,51). Shapiro et al. (40) studied gender related differe nces in ten men and nine women under several different hot wet and hot dry conditions Men sweated more than women in all climates. The most signifi cant difference was during hot wet exposures, where men sweated 25-40% more than women. The average sweat rates were 557 and 423 gm-2h-1, respectively. Conversely, some studies report no differe nce in SR between men and women. Moran et al. (45) found no di fference between men and women with similar aerobic capacities at the same exposure. The group of fit men had a significantly higher SR than women at the high exercise intensity (650 W). In addition, Frye a nd Kamon (42) studied

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12 four men and four women of similar fitness levels pre and post acclimation. There was no difference in post-acclimation SR. These resu lts coupled with those from Moran et al. (45) infer that the acclimation process and the matching of partic ipants on fitness can reduce gender differences in SR. Heart Rate Generally, there is an increase in heart ra te (HR) as the level of heat stress increases. Research on the gender differen ce in HR during heat stress is conflicting. Avellini, Kamon and Krajewski (51) examined responses of physically fit men (n=4) and women (n=4) with comparable maxi mal aerobic capacities (64.2 and 65.7 ml/kg, respectively) and equal body surf ace areas to acclimation to humid heat. Participants underwent a three-hour heat stress test (Tdb = 36C, Twb = 30C, VO2 = 1.0 L/min) before and after a ten-day acclimation to humid heat. Before acclimation, men and women began experiments with similar resting HR va lues. However, men had higher HR values than women during 30, 60, and 90 minutes of ex ercise. When expressed as a percentage of resting HR, there were no differences between genders in exercising HR. Post acclimation, men had significantly greater HRs than women at 90 min as well as a significantly higher HR during the 3rd hour of the experiments. This could have been caused by a high SR during the experiment th at could not be replaced through ad libitum water ingestion or a reduction in SR since wo men rely more on convective heat loss. In this same study, no post-acclimation differences in HR were found between men and women during the first 1.5 hours of the experiment.

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13 Paolone et al. (41) and Keatisuwan, Tadakatsu, and Tochihara (44) found higher HRs in men during heat stress experiments. Keatisuwan et al. (44) exposed men and women to hot dry (Tdb = 40C, RH = 30%) and hot wet (Tdb = 31C, RH = 80%) environments while performing work rest cycl es. During work, participants pedaled on a bicycle ergometer at 40% VO2max. Paolone had subjects work at 50% VO2max in neutral (Tdb = 25C, Twb = 18C), warm (Tdb = 32C, Twb = 34C), and hot environments (Tdb = 40C, Twb = 31C) where RH was held to 5055%. Environmental exposures were two hours divided into work, rest, and recove ry. The higher HRs for men in both studies could be explained by the fact that participan ts were not matched on fitness and that the men had a greater level of heat stress with an elevated need for skin blood flow. In several studies, when participants we re matched on fitness, there were no differences between genders in HR (42,42,44,45,51). However, when participants are not matched on fitness and exercise at an equi valent absolute workload, the women are working at a higher relative workload resulting in a higher HR (49,47,45). Kamon, Avellini, and Krajewski (49) reported a hi gher heart rate for women (P<0.05) at the critical condition, the point between compen sable and uncompensable heat stress. McLellan (47) also found higher HRs in women under conditions of compensable heat stress. As discussed in a previous secti on, Moran et al. (45) ex amined three groups of participants while exercising under controlled conditions of compensable heat stress. No difference was found in HR between the men and women matched on fitness. However, the women had a significantly higher (P<0.05) HR than the fit men. Yousef et al. (48) and Shapiro et al. (40) both conducted experiments with partic ipants of different fitness

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14 levels in hot dry environments and repor ted a higher HR in women. A hot dry environment can emphasize the effect of diffe rent fitness levels due a lower rate of evaporative heat loss in women, leading again to higher HR. Core Temperature Most investigators found no diffe rence in core temperature (Tre) between genders when matched on fitness (42,42,45,51) or when exercising at an equivalent MR (42,41,44,52). However, in hot dry environments, Tre tends to be higher in women due to their physiologic preference to dissipate heat through convective means (40,48). The female participants in the study by Yousef et al. (48) had higher Tre than the men. Comparably, Shapiro et al (40) found that whil e exercising in hot wet environments, men tend to have higher Tre due to the decreased ability to dissipate heat through sweat evaporation. In conclusion, di fferences between genders in physiological responses tend to disappear wh en subjects are matched on fitness, body size, acclimation state, and ambient environment in which ex ercise takes place are standardized. Physiological Strain Index A physiological strain index (PSI) deve loped by Moran, Shitzer, and Pandolf (53) is based upon Tre and HR as “representativ e of the combined strain reflected by the thermoregulatory and cardiovascular systems ( 45).” The index rate s physiological strain on a scale of 0-10 and is cal culated as follows (53): PSI = 5(Tre t – Tre0) • (39.5 – Tre0)-1 + 5(HRt – HR0) • (180 – HR0)-1 [3] Where Tre t and HRt are simultaneous measurements taken at any time during exposure and Tre0 and HR0 are the initial measurements.

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15 Moran et al. (45) examined the ability of PSI as a tool to assess differences between genders during heat strain at various exercise intensities and climates. As discussed previously, three groups of acclimated participants exercised at low, moderate, and high intensities in comforta ble, hot wet, and hot dry environments. The participant groups consisted of eight men (M) matched on fi tness to a group of nine women (W), and a group of eight men (MF) that were more fit than the first two groups. In general, PSI values increased with exercise intensity and heat load. No significant difference in PSI was found between M and F at the same exposure. However, MF had a significantly lower strain than the matched groups. Speci fically, significant differences between M and MF were found during moderate exercise in the hot wet (PSIM = 6 and PSIMF = 4) and hot dry (PSIM = 5 and PSIMF = 4) climates. During high in tensity exercise, there were significant differences between M and MF in all three environments. When PSI was applied from the beginning to the end of experiments across all three environments, ranking was as follows: low exercise intensity – little to low strain with values of 2-4, moderate exercise intensity – little to m oderate strain with values of 2-6, and high exercise intensity – low to very high strain with values of 2-9 (45). Hypothesis The purpose of this study was to examin e gender differences in response to heat stress at critical WBGT across a range of clothing ensembles. There were two null hypotheses to be tested. In the first, the null hypothesis is that there are no differences in WBGTcrit between women and men among five clothi ng ensembles. If there is a failure to reject the first hypothesis, s uggesting that the levels of h eat stress are the same, then

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16 differences in physiological response can be at tributed to populati on characteristics based on gender. Thus the second null hypothesis is that there are no differences between women and men in their physiologica l response to heat stress at WBGTcrit across clothing ensembles.

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17 METHODS The purpose of this project was to populati on differences in heat stress and strain attributable to gender. The progressive e xperimental protocol fixed metabolic demand and level of relative humidity (RH). Determ ination of the point of transition from compensable to uncompensable heat st ress was the critical condition. Participants The study included twenty-nine adults (n ine women and twenty men). Their physical characteristics can be found in Appe ndix A and means and standard deviations of their physical characteri stics by gender are provided in Table 1. A subset of participants included 15 adults (four wome n and eleven men) from the main study. Subset participant physical characteristics are provided in Appendix A. Means and standard deviations of their physical characteristics by gender are provided in Table 2. All participants were recruited from the Tampa Bay area using local print media and campus advertising at the University of South Florida. They were employed for three weeks and compensated on a per experi ment basis. Participants were first interviewed by an investigator for the purpos e of explaining the study and to determine interest and availability. A physician conducted a physical examination and written consent was obtained before participants coul d begin experiments. Women self reported results of a home pregnancy test.

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18 Table 1 Summary of Participant Characteristics Age Height (cm) Weight (kg) BSA (m2) Women (n = 9) Mean 28 163 63.7 1.74 Std Dev 8 7 16.6 0.29 Men (n = 20) Mean 29 179 88.7 2.07 Std Dev 9 34 23.2 0.41 Both (n = 29) Mean 29 174 80.9 1.97 Std Dev 8 12 20.2 0.28 Table 2 Summary of Sub-Study Participant Characteristics Age Height (cm) Weight (kg) BSA (m2) Women (n = 4) Mean 23 165 64.2 1.70 Std Dev 5 6 18.0 0.22 Men (n = 11) Mean 28 176 81.7 1.98 Std Dev 10 11 12.0 0.47 Both (n = 15) Mean 27 173 77.0 1.91 Std Dev 9 11 15.4 0.22 Clothing Five clothing ensembles were evaluated. 1. Work clothes: 4oz/yd cotton long sl eeve shirt, 8oz/yd cotton pants 2. Cotton coveralls: 10oz/yd2 3. Particle barrier coveralls (limite d use): Tyvek 1424 or Tyvek 1427 4. Water barrier, vapor permeable coveralls (limited use): NexGen LS417

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19 5. Vapor barrier coveralls (limited use): Tychem QC, polyurethane coated Tyvek The non-woven coveralls had a zipper cl osure in the front, elastic cuffs and ankles. Athletic shoes and socks, shorts, underwear, cotton t-shirt, and sports bra for women were worn underneath all ensembles. Equipment Each experiment was conducted in a Fo rma Scientific 7010 climatic chamber. The dimensions inside the chamber were 2.7 me ters wide x 3.0 meters deep x 2.2 meters high. The temperature and humidity range capabilities of the ch amber were 4 to 60 C and 10 to 90% RH. Air speed could also be controlled. Participants walked on a motorized tread mill (Stair Master Club Track) on which metabolic rate (MR) was controlled through speed and slope. Heart rate (HR) was monitored using a Polar Electro Heart Rate Mo nitor. Rectal temperature was measured using a flexible thermister (YSI 401AC) inse rted 10cm past the anal sphincter muscle. Tsk was monitored at four sites (chest upper arm, thigh, calf) using YSI 409A thermisters. Average Tsk was computed using the follo wing equation (need reference): Tsk = 0.3Tchest + 0.3Tarm + 0.2Tthigh + 0.2Tcalf. [4] Calibration of thermisters was performed prior to each experiment using a hot water bath. MR was assessed every half hour duri ng experiments by measuring the volume and composition of expired air. Expired ga ses were collected by having the participant breathe through a two-way valve into a Dougl as bag for 2-3 minutes. The collected volume of air was then measured using a dry gas meter and the oxygen content was

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20 measured using an oxygen analyzer (Beckma n E2), which was calibrated before each experiment. Oxygen consumption was dete rmined using the following equation (54). VO2 = VE O2/100 CF [5] Where VE = expired air flow rate (L/min) O2 = difference in percent of oxygen between inspired and expired air CF = correction factor to convert volume to STDP Protocols Acclimation Each participant underwent a five-day acclimation period consisting of two hours in the climatic chamber per day. The e nvironment in the chamber was held at 50 C and 20% RH. Participants walked on the treadmill at a speed that would elicit a metabolic rate normalized to body surface ar ea (MSA) of approximately 160W/m2. Acclimation trials lasted two hours or until one of the termination criteria was met. Experimental Sessions Experiments were conducted in each of the five ensembles in a moderate environment, initially held constant at 34C and 50% RH. Treadmill speed and grade were set to elicit a MSA of approximately 160 W/m2. When the participants reached thermal equilibrium (no change in HR or Tre for 15 minutes), Tdb was increased 1C every 5 minutes. Tre, HR, and ambient conditions were mon itored continuously and recorded every five minutes. Tsk at four sites was recorded every te n minutes. Participants were allowed

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21 to drink water or a commercial flui d replacement beverage as desired. Trials lasted approximately 120 minutes unl ess termination criteria were met. Termination criteria included successful comple tion of the trial (determination of critical conditions), a Tre above 39 C, a HR of 90% age-predicte d max, or by request of the participant. The order in which the five ensembles were worn during trials was randomized, with any necessary repeats completed at the end of the three-week period. Critical Conditions WBGT exposure limits are based upon an inflection point, or the point at which the body can no longer maintain thermal equilibrium. The critical condition was determined for each experiment by noting the chamber conditions 5 minutes before a significant increase (0.1 C or more) in Tre. The critical WBGT was then computed using O’Connor and Bernard’s method (10). WBGTcrit = 0.7 (Tpwb + 1.0) + 0.3Tg [6] Statistical Analysis Data were analyzed using a mixed m odel analysis of variance. Level of significance was set at 0.05. From a complete data set, we extr acted trials of one metabolic level (160W/m2) and one environmental condition (50%RH). Analysis included ANOVA evaluating the di fferences in MR, MSA, WBGTcrit, and physiological responses by gender and by ensemble. Subjec ts were nested with in gender for all analyses. The interaction of gender and ense mble was also examined. From the subset of data, ANOVA evaluated differences in WBGTcrit, MSA, and physiological responses

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22 (Tre, HR, Tsk, and PSI) by metabolic level, by gende r, and by ensemble. Subjects were nested within gender. The interaction of gender and ensemble was examined followed by the interaction of gender and metabolic level.

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23 RESULTS The current study included a primar y population of 20 men and 9 women described in Table 1, and a sub-study population from the main group that included 11 men and 4 women (Table 2). Level of Heat Stress The study design called for a targ et metabolic rate of 160 W/m2. Table 3 gives the absolute (MR) and normalized metabolic rates (MSA) by gender for the group average and standard deviation. A tw o-way analysis of variance (ANOVA) (subjects nested in gender by ensemble) revealed a significant gender difference (p< .0001) for MR, and for MSA (p< .0001). MR was greater for me n than for women (347 W and 270 W, respectively). Men had a significant ly greater MSA than women (172 W/m2 and 152 W/m2, respectively). There were no differen ces in MSA (p = 0.519) or MR (p = 0.372) among ensembles. Results critical WBGT (WBGTcrit) as mean and standard deviation by gender and ensemble are reported in Table 4. Figur e 1 illustrates the m ean WBGTcrit values by ensemble. A two-way ANOVA (subjects nested in gender by ensemble) was used to determine statistical significance for gender and ensemble as well as the interaction. There were significant differences (p = 0.035) between genders for WBGTcrit where the mean values were 32.5C for men and 33.1C fo r women. There was also a significant difference for WBGTcrit among ensembles (p<0.0001). Tychem, the vapor barrier

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24 ensemble was the lowest at 27.3C. Work clothes (34.8C) and co tton coveralls (34.9C) produced the highest WBGTcrit. Table 3 Means and Standard Deviations of Metabolic Rate MR (W) MSA (W/m2) Women Mean 270 152 Std Dev 68 34 Men Mean 347*** 172*** Std Dev 58 30 Both Mean 322 165 Std Dev 71 32 *** Significant difference from Women (P<.0001) Table 4 Critical WBGT (WBGTcrit C) for Men, Women, and Both Wearing All Ensembles Work Clothes Cotton Coveralls Tyvek NexGen Tychem All Women Mean 34.9 35.5 34.1 32.9 27.9 33.1 Std Dev 1.6 1.7 0.8 1.6 1.9 3.1 Men Mean 34.8 34.7 34.1 32.1 27.1 32.5*** Std Dev 2.1 1.4 1.5 1.3 1.6 3.3 Both † Mean 34.8a 34.9a 34.1a 32.3b 27.3c Std Dev 1.9 1.5 1.3 1.5 1.7 *** Significant difference between Men and Women (p<.0001), † Values with like letters are not statistically different (p<.05)

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25 26.0 28.0 30.0 32.0 34.0 36.0 38.0 Work ClothesCotton Coveralls TyvekNex GenTyChemAllEnsembleWBGTcrit Women Men Figure 1 Comparison of WBGTcrit for men and women in all ensembles. Heat Strain Mean values and standard deviations for Tre for men and women in all five ensembles are reported in Table 5. Figure 2 depicts the mean Tre values by ensemble. Two-way ANOVA procedures re vealed no significant differe nce between genders (p = 0.055) for Tre. There were also no si gnificant differences in Tre among ensembles (p = 0.990) and for interactions (p = 0.249). Table 5 Core Temperature (Tre C) Means and Standard Deviations at the Critical Condition for Men, Women, and Both Wearing All Ensembles Work Clothes Cotton Coveralls Tyvek NexGen Tychem All Women Mean 37.8 37.8 37.7 37.8 37.9 37.8 Std Dev 0.4 0.3 0.3 0.3 0.3 0.3 Men Mean 37.8 37.7 37.8 37.7 37.7 37.7 Std Dev 0.2 0.2 0.3 0.3 0.3 0.3 Both Mean 37.8 37.7 37.8 37.7 37.8 Std Dev 0.3 0.3 0.3 0.3 0.3

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26 37.0 37.5 38.0 38.5 Work Clothes Cotton Coveralls TyvekNex GenTyChemAllEnsembleTre Women Men Figure 2 Comparison of Tre at WBGTcrit for men and women in all ensembles. Means and standard deviations of HR at the critical condi tion are reported in Table 6. The mean values for HR are shown in Figure 3. The two-way ANOVA revealed that women (HR = 125 bpm) had a significantly higher HR than men (HR = 112 bpm). There was no significant difference among ensembles (p = 0.926) and there was no interaction in HR between gende r and ensemble (p = 0.385). Table 6 Heart Rate (HR) at the Critical Cond ition for Men, Women, and Both Wearing All Ensembles Work Clothes Cotton Coveralls Tyvek NexGen Tychem All Women Mean 120 127 123 126 129 125 Std Dev 15 16 14 16 18 16 Men Mean 115 111 112 109 111 112*** Std Dev 17 13 14 13 19 15 Both Mean 116 116 116 114 117 Std Dev 17 16 15 15 20 *** Significant difference be tween women and men (p<.0001)

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27 100 110 120 130 140 150 Work Clothes Cotton Coveralls TyvekNex GenTyChemAllEnsembleHR Women Men Figure 3 Comparison of HR at WBGTcrit for men and women in all ensembles. For weighted mean skin temperature (Tsk) means and standard deviations are reported in Table 7. The mean values for Tsk are represented graphically in Figure 4. Women had a significantly hi gher mean value than men (Tsk = 36.4 C and 36.2 C, respectively). There were no differe nces among ensembles (p = 0.767) and no interactions (p = 0.678). Table 7 Skin Temperature (Tsk C) at the Critical Condition for Men, Women, and Both Wearing All Ensembles Work Clothes Cotton Coveralls Tyvek NexGen Tychem All Women Mean 36.4 36.6 36.3 36.4 36.5 36.4* Std Dev 0.5 0.6 0.8 0.4 0.8 0.6 Men Mean 36.3 36.3 36.3 36.1 36.1 36.2 Std Dev 0.5 0.5 0.5 0.5 0.8 0.6 Both Mean 36.3 36.4 36.3 36.2 36.2 Std Dev 0.5 0.5 0.6 0.5 0.8 Significant difference between Women and Men (p<.05)

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28 35.5 36.0 36.5 37.0 37.5 Work Clothes Cotton Coveralls TyvekNex GenTyChemAllEnsembleTsk Women Men Figure 4 Comparison of Tsk at WBGTcrit for men and women in all ensembles. The means and standard deviations for PSI are reported in Table 8. The mean values for PSI are presented graphically in Figure 5. There was a significant difference between genders, where the value for me n was 3.80 1.01 compared to 4.53 1.16 for women. As reported for all of the physiol ogical responses, ther e were no significant differences in PSI among ensembles (p = 0.961) and there were no interactions (p = 0.245) between gender and ensemble. Table 8 PSI at the Critical Cond ition for Men, Women, and Both Wearing All Ensembles Work Clothes Cotton Coveralls Tyvek NexGen Tychem All Women Mean 4.3 4.7 4.3 4.6 4.8 4.5*** Std Dev 1.3 1.0 1.2 1.1 1.3 1.2 Men Mean 4.0 3.7 3.9 3.6 3.8 3.8 Std Dev 1.0 0.9 1.0 0.8 1.4 1.0 Both Mean 4.1 4.0 4.1 4.0 4.1 Std Dev 1.1 1.0 1.0 1.0 1.4 *** Significant difference be tween Women and Men (p<.0001)

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29 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 Work Clothes Cotton Coveralls TyvekNex GenTyChemAllEnsemblePSI Women Men Figure 5 Comparison of PSI at WBGTcrit for men and women in all ensembles. In summary (Table 9), there were no differences among ensembles in Tre, HR, Tsk, and PSI. There was also no difference in Tre between genders. There were differences between genders for HR (p<0.0001), average Tsk (p = 0.034), and PSI (p<0.0001). Table 9 Summary of Differences Between Gender and Among Ensembles for Physiological Responses Gender Ensemble Tre NS NS HR <0.0001 NS Tsk 0.0338 NS PSI <0.0001 NS Effect of Metabolic Rate The average MSA during experiments was 165 W/m2. But, men had an MSA that was 20 W/m2 higher than women. To evaluate th e effects of metabolic level on gender differences in physiological response to heat stress, a subset of the data using three

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30 metabolic levels was examined. The relations hip of change in MSA to the difference in WBGTcrit and all physiological responses (HR, Tre, Tsk, and PSI) was investigated. Slope is the ratio of change in one variable (the metrics of WBGTcrit, HR, Tre, Tsk, PSI) for a given change in the another vari able (the confounder, MSA). Slopes for the metrics were computed with a least squares f it through three points. The slope values are reported in Table 10 for women, men and both. Table 10 Relationship of WBGTcrit and Physiological Responses to Normalized Metabolic Rate (MSA) M1 M2 M3 Slope MSA (W/m2) Women 103 173 245 Men 120 186 259 Both 112 180 252 WBGTcrit (C) Women 35.7 32.8 29.5 -0.044 Men 35.2 32.4 30.2 -0.036 Both 35.4 32.6 29.9 -0.039 HR (bpm) Women 115 126 141 0.18 Men 108 114 125 0.12 Both 111 120 133 0.16 Tre (C) Women 37.6 37.8 37.9 0.0021 Men 37.5 37.7 38.0 0.0036 Both 37.5 37.8 37.9 0.0028 Tsk (C) Women 36.8 36.3 35.3 -0.011 Men 36.6 36.3 35.7 -0.0065 Both 36.7 36.3 35.5 -0.0086 PSI (C) Women 3.7 4.5 5.5 0.013 Men 3.2 3.9 4.8 0.012 Both 3.4 4.2 5.2 0.013 Adjusted values for WBGTcrit and physiological responses were calculated by multiplying the slope of the metric variable for both women and men by the difference in MSA between men and women and adding that adjustment to women. Results are

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31 reported in Table 11. In additi on, the level of statis tical significance of the difference is provided. Table 11 Adjusted Values of WBGTcrit and Physiological Responses Based on the Difference in MSA Men Women Menadjusted Result P MSA (W/m2) 172 152 WBGTcrit 32.5 33.1* 33.2 NSD 0.45 Tre 37.7 37.8 37.6 W > M <0.001 HR (bpm) 112 125* 109 W > M <0.0001 Tsk 36.2 36.4* 36.4 NSD 1.0 PSI 3.8 4.5* 3.54 W > M <0.0001 Significant difference between genders before adjustment

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32 DISCUSSION Gender differences in WBGTcrit and associated physiological variables were explored for five clothing ensembles unde r moderate environmental conditions and a fixed moderate metabolic rate. Level of Heat Stress Because normalized metabolic rate was a c ontrolled variable in the experimental design, it is important to conf irm that it was adequately cont rolled. In fact, there was a significant gender difference in MS A, where the men were 20 W/m2 or 11% higher than the women. This could lead to a bias toward lower WBGTcrit for men. The difference was 0.6 C-WBGT, and statistica lly significant. From Table 11, the ratio of change for WBGTcrit divided by normalized metabo lic rate was -0.039 C-WBGT W-1 m2. CortsVizcaino and Bernard (55) found a ratio of -0.018 and O’Conner and Bernard (10) found a ratio of -0.007. This would suggest that the observed mean male WBGTcrit could be between 0.1 and 0.8 C-WBGT lower because of the higher metabolic rate. Kenney and Zeman (56) looked at unacclimated semi-clo thed men and women at the upper limit of compensable heat stress, where WBGTcrit, was 31.3C for men and 32.3C for women and the metabolic rate differed by 52 W/m2 (M = 191, W = 139 W/m2). The ratio of change for WBGTcrit divided by normalized metabo lic rate was -0.02 C-WBGT W-1 m2. The adjusted mean value of WBGTcrit for women was 31.3C, equating the values for men and women and equating the heat loa d. The differences in MSA could be a

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33 plausible explanation for the gender difference in WBGTcrit. While there were differences in normalized metabolic rate and WBGTcrit, the differences were small and compensatory. There was no interaction of gender and clothing on WBGTcrit and the effects of clothing were described by Be rnard, Luecke, Schwartz, Kirkland, and Ashley (57). For this reason the level of heat stress was considered equivalent for women and men. Heat Strain at WBGTcrit The women in this study had a greater heart rate (HR) (125 bpm) than the men (112 bpm), where the subjects were acclima tized and worked at the upper limit of compensable heat stress. These results are in accordance with other investigators (40, 49) who found a difference of 15-20 bpm between men and women exercising at the same absolute workload and environmental conditions Further, in studi es where there were equivalent relative demands in the same e nvironment (41,48), heart rate was still greater in women than in men. When there are equal relative demands and uneven absolute demands in the same environment, MRs on av erage are different and the heat stress is different. There is a lower requirement for peripheral blood flow for women and therefore a lower heart rate. Here, part of the gender difference may be masked. On the other hand, Frye and Kamon (42) reported equivalent HRs for acclimatized men and women at the critical condition. Their subj ects were matched on aerobic capacity which would reduce differences in thermoregulation and equalize heat stra in between men and women. In looking at gender differences in HR in response to compensable or uncompensable heat stress, the findings in the current study were in li ne with others in

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34 finding a higher HR response when there is no matching of subjects based on aerobic capacity. Therefore, the fact that women in this study had a higher heart rate was due to a higher relative demand as well as the heat. The results of this study examining the effects of an intermediate humidity on heat strain while working at the same workload found that Tre was about the same for women (37.8 C) and men (37.7 C) at the critical condition. Other studies that evaluated Tre while participants exercised at the same ab solute workload also reported equivalent Tre for men and women (49,40,47). The lack of difference between genders was also reported in studies where participants exerci sed at equivalent rela tive demands (41,44). Frye and Kamon (42) matched thei r subjects on aer obic fitness (VO2 max = 54 and 56 ml kg-1 min-1 for women and men, respectively) and they were acclimatized. The matching removed an important difference due to gende r (i.e., population differences in fitness) and helped to explain the ab sence of a difference in Tre in their study. Kamon, Avellini and Krajewski (49) evaluated men and women exercising at the same absolute workload at critical conditions. The average difference in Tre between the men (37.94 C) and women (38.02 C) was not statisti cally significant but was si milar to the current study (0.08 versus 0.1 in the present study). The current study revealed a gender difference in skin temperature (Tsk), with average values of 36.4C and 36.2C for women and men, respec tively. These results are in line with those of other st udies (40,45,47) that also repo rted women to have a higher average Tsk for women working at the same workload as men. Yousef et al. (48) also reported a higher Tsk for women (+0.1C); even under e quivalent relative demands where

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35 the magnitude of the difference may be not be as evident. Several other studies (49,42,42,44,51) reported no difference in Tsk between men and women. Frye et al. (42) and Sawka, Toner, Francesconi, and Pandol f (45) found no gender difference between men and women who were matched on fitne ss. As discussed earlier, the matching removed the difference due to gender and expl ains the absence of a difference between men and women in Tsk. Physiological Strain Index (PS I) is a composite index using Tre and HR to reflect the combined strain of the thermoregulator y and cardiovascular system. Due to the gender differences in heart rate, it was not surprising that women had a higher PSI than men. Moran et al. (45) found no gender differe nce in PSI. However, in their study there did appear to be a difference in PSI based on fitness with the group of fit men having a lower PSI than the unmatched (less fit) wome n. The subjects in the current study were not matched on fitness, the women recruite d from the university and community were probably less fit than the men further explaining the gender difference in PSI. Effects of Metabolic Rate To evaluate the effects of unequal normalized metabolic level on gender differences in physiological response to heat stress, a subset of the data using three metabolic levels was evaluated. The av erage metabolic rates were 112, 180, and 252 W/m2. The metabolic rates normalized to body surface area for men were approximately 15 W/m2 greater than women at each level of metabo lic rate. As this might bias men to a lower WBGTcrit and higher core temperatures and hear t rates, the slope (ratio of change in the physiological metric divided by the change in normalized metabolic rate) was

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36 calculated for WBGTcrit, HR, Tre, Tsk and PSI. The values of the physiological metrics were adjusted accordingly for the differences in metabolic rate. The ratio of change for WBGTcrit was -0.039C-WBGT/W m-2. In this study the average metabolic rate difference was 20 W/m2 greater for men. The mean male critical WBGT was approximately 0.7C lower than for the women. Adding 0.7 C-WBGT to adjust for this bias would make the criti cal WBGT for men 33.2 C-WBGT, nearly the same as women (33.1 C-WBGT). The adjust ed value results in no statistical gender difference in WBGTcrit. Kamon, Avellini and Krajewski (49) evaluated WBGTcrit while participants exercised at the same absolute workload. Their resu lts further support our findings of no difference in WBGTcrit; and this adjustment provided a means to make the heat stress level equivalent. The ratio of change for HR was 0.16 bpm/W m-2, providing an adjusted mean difference in heart rate for men of 3.2 bpm, still resulting in a significant difference in HR (109 for men versus 125 for women). These re sults are concordant with those of Kamon, Avellini and Krajewski (49). They found a difference in heart rate of 18 bpm and reported that the difference in HR is proporti onal to the difference in aerobic capacity in their subjects. This is supported by the wo rk of Frye and Kamon (42) who reported no difference in heart rate in acclimated men and women who we re matched on aerobic capacity. The adjustment for Tre resulted in an adjusted mean Tre for men of 37.6C, a slightly, but significantly, lower Tre than the women (37.8). Kamon et al. (49) found similar results although the difference between genders was not significant. In their

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37 study, the average Tre for women was 38.0C and the average for men was slightly lower at 37.9C. The ratio of change for Tsk was -0.0086C-Tsk/W m-2. The adjusted mean Tsk for the men was approximately 0.2C lower than fo r the women. Adding 0.2 C to adjust for this bias would make the Tsk for men 36.4C. The adjusted mean resulted in no statistical gender difference in Tsk. This is in agreement with Kamon et al. (49) who found no statistically significant difference in average Tsk between acclimated men and women exercising at the upper limit of compensable heat stress. The men had a PSI that was 0.7 lower than the women. The ra tio of change for PSI was 0.013 PSI/W m-2. The adjusted mean PSI for the men was approximately 0.26 higher. Subtracting 0.26 to adjust for this bias would make the PSI for men 3.54, still yielding a significant gender difference in PSI. When the metabolic level is adjusted for subjects to approximate equivalent metabolic and heat loads, the major gender difference was still in HR. When subjects are not matched on aerobic fitness, women appear to experience a greater cardiovascular strain at the upper limit of compensable heat stress. Conclusion In conclusion, there is no gender difference in WBGTcrit in acclimatized participants wearing a broad range of pr otective clothing ensembles when normalized metabolic level is similar. At similar heat stress levels, at the upper limit of compensable heat stress at a moderate rate of work, wo men did experience a grea ter cardiovascular

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38 strain evidenced by a greater HR. Followi ng HR, PSI was also elevated for women. There were no real differences in core and skin temperatures.

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39 REFERENCES 1 American Conference of Governme ntal Industrial Hygienists. (2006). Threshold limit values and biological exposure indices Cincinnati, OH: Author. 2 Lind, A. R. (1963). A physiological criteri on for setting thermal environmental limits for everyday work. Journal of Applied Physiology 18 51–56. 3 National Institute of Occupational Safety and Health. (1986). Criteria for a recommended standard: Occupational exposure to hot environments (DHHS [NIOSH] Publication No. 86-113).Was hington, DC: Author. 4 Belding, H. S., & Kamon, E. (1973). Evaporat ive coefficients for prediction of safe limits in prolonged exposures to work under hot conditions. Federation Proceedings 32 1598–1601. 5 Kenney, W. L., Mikita, D. J., Havenit h, G., Puhl, S. M., & Crosby, P. (1993). Simultaneous derivation of clothing-sp ecific heat exchange coefficients. Medicine and Science in Sports and Exercise 25 283–289. 6 Barker, D. W., Kini, S., & Bernard, T. E. (1999). Thermal characteristics of clothing ensembles for use in heat stress analysis. American Industria l Hygiene Journal 60 32– 37. 7 International Organization for Standardization. (1989). Hot environments—Estimation of the heat stress on working man, based on the WBGT (wet bulb globe temperature) index (ISO 7243). Geneva: Author. 8 Harm, D. L., Jennings, R. T., Meck, J. V., Po well, M. R., Putcha, L., Sams, C. P., et al. (2001). Invited review: Gender issues rela ted to spaceflight: A NASA perspective. Journal of Applied Physiology 91 2374–2383. 9 Cheung, S. S., McLellan, T. M., & Tena glia, S. (2000). The thermophysiology of uncompensable heat stress: Physiological mani pulations and individu al characteristics. Sports Medicine 29 329–359. 10 O’Connor, D. J., & Bernard, T. E. (1999). Continuing the search for WBGT clothing adjustment factors. Applied Occupational and Environmental Hygiene 14 119–125. 11 Kenney, W. L. (1987). Adjustme nts for protective clothing. American Industrial Hygiene Association Journal 48 576–577.

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40 12 Kenney, W. L., Hyde, D. E., & Bernard, T. E. (1993). Physiol ogical evaluation of liquid-barrier, vapor-permeable protectiv e clothing ensembles for work in hot environments. American Industrial Hygiene Journal 54 397–402. 13 Paull, J. M., & Rosenthal, F. S. (1987). H eat strain and heat stress for workers wearing protective suits at a hazardous waste site. American Industrial Hygiene Journal 48 458– 463. 14 Reneau, P. D., & Bishop, P. A. (1996). A review of the suggested wet bulb globe temperature adjustments for encap sulating protective clothing. American Industrial Hygiene Journal 57 58–61. 15 Cheung, S. S., & McLellan, T. M. (1998) Heat acclimation, aerobic fitness, and hydration effects on tolerance duri ng uncompensable heat stress. Journal of Neurophysiology 84 1731–1739. 16 Schvartz, E., Saar, E., Meyerstein, N., & Benor, D. (1973). A comparison of three methods of acclimatization to dry heat. Journal of Applied Physiology 34 214–219. 17 Horstman, D. H., & Christensen, E. (1982) Acclimatization to dry heat: Active men vs. active women. Journal of Applied Physiology 52 825–831. 18 Pichan, G., Sridharan, K., Swamy, Y. V ., Joseph, S., & Gautam, R. K. (1985). Physiological acclimatization to heat afte r a spell of cold conditioning in tropical subjects. Aviation, Space, and Environmental Medicine 56 436–440. 19 Griefan, B. (1997). Acclimation to three di fferent hot climates with equivalent wet bulb globe temperatures. Ergonomics 40 223–234. 20 Wagner, J. A., Robinson, S., Tzankoff, S. P., & Marino, R. P. (1972). Heat tolerance and acclimatization to work in the heat in relation to age. Journal of Applied Physiology 33 616–622. 21 Henschel, A., Tayler, H. L., & Keys A. (1943). The persistence of heat acclimatization in man. American Journal of Physiology 140 321–325. 22 Sawka, M. N., Latzka, W. A., & Montai n, S. J. (2001). Physiologic tolerance to uncompensable heat: Intermittent exercise, field vs. laboratory. Medicine and Science in Sports and Exercise 33 422–430.

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41 23 American College of Sports Medicine. (2000). ACSM’s guidelines for exercise testing and prescription (6th ed.). New York: Lippincott, Williams, & Wilkins. 24 Givoni, B., & Goldman, R. F. (1973). Pred icting effects of heat acclimatization on heart rate and rectal temperature. Journal of Applied Physiology 35 875–879. 25 Griefahn, B. (1997). Acclimation to three di fferent hot climates with equivalent wet bulb globe temperatures. Ergonomics 40 223–234. 26 Stephens, R. L., & Hoag, L. (1981). Heat acclimatization, its decay, and reinduction in young Caucasian women. American Industrial Hygiene Association Journal 42 12–17. 27 Lim, C. L., Chung, K. K. C., & Hock, L. L. K. (1997). The effects of prolonged passive heat exposure and basic military trai ning on thermoregulatory and cardiovascular responses in recruits from a tropical country. Military Medicine 162 623–627. 28 Pandolf, K. B., Burse, R. L., & Goldman, R. F. (1977). Role of physical fitness in acclimatization, decay and reinduction. Ergonomics 20 399–408. 29 MiTrechell, D., Senay, L. C ., Wyndham, C. H., van Rensbur g, A. J., Rogers, G. G., & Strydom, N. B. (1974). Acclimatization in a hot, humid environment: Energy exchange, body temperature, and sweating. Journal of Applied Physiology 40 768–778. 30 Nadel, E. R., Pandolf, K. B., Roberts, M. F., & Stolwijk, J. A. (1974). Mechanism of thermal acclimation to exercise and heat. Journal of Applied Physiology 37 515–520. 31 Nielson, B., Strange, S., Christensen, N. J., Warberg, J., & Saltin, B. (1997). Acute and adaptive reponses in humans to ex ercise in a warm, humid environment. European Journal of Physiology 434 49–56. 32 Occupational Safety and Health Administration. (1999). Protecting workers in hot environments Cincinnati, OH: U.S. Department of Labor. 33 Gill, N., & Sleivert, G. (2001). Effect of daily versus in termittent exposure on heat acclimation. Aviation, Space, and Environmental Medicine 72 385–391. 34 Williams, C. G., Wyndham, C. H., & Morr ison, J. F. (1967). Rate of loss of acclimatization in summer and winter. Journal of Applied Physiology 11 197–198. 35 Wilmore, J. H. (2003). Aer obic exercise and endurance. The Physician and Sports Medicine 31 (5). Retrieved February 19, 2006, from http://www.physsportsmed.com

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42 36 Aoyagi, Y., McLellan, T. M., & Shephar d, R. J. (1997). Interactions of physical training and heat acclimation: The therm ophysiology of exercising in a hot climate. Sports Medicine 23 173–210. 37 McArdle, W. D., Katch, F. I., & Katch, V. L. (1996). Exercise physiology: Energy, nutrition, and human performance, 4th Edition Baltimore: Williams and Wilkins. 38 Pascoe, D. D., Shanley, L. A., & Smith, E. W. (1994). Clothi ng and exercise I: Biophysics of heat transfer between the individual, clothing, and environment. Sports Medicine 18 38–54. 39 Kenney, W. L. (1985). A review of compara tive responses of men and women to heat stress. Environmental Research 37 1–11. 40 Shapiro, Y., Pandolf, K. B., Avellini, B. A., Pimental, N. A., & Goldman, R. F. (1980). Physiological responses of me n and women to humid and dry heat. Journal of Applied Physiology: Respiratory, En vironmental and Exercise Physiology 49 1–8. 41 Paolone, A. M., Wells, C. L., & Gerar d, T. K. (1978). Sexual variations in thermoregulation during heat stress. Aviation, Space, and Environmental Medicine 49 715–719. 42 Frye, A. J., & Kamon, E. (1981). Responses to dry heat of men and women with similar aerobic capacities. Journal of Applied Physiology : Respiratory, Environmental and Exercise Physiology 50 65–70. 43 Sawka, M. N., Toner, M. M., Frances coni, R. P., & Pandolf, K. B. (1983). Hypohydration and exercise. Journal of Applied Physiology 55 1147–1153. 44 Keatisuwan, W., Tadakatsu, O., & Tochihar a, Y. (1996). Physiological responses of men and women during exercise in hot environments with equivalent WBGT. Applied Human Science: Journal of Physiological Anthropology 15 249–258. 45 Moran, D. S., Shapiro, Y., Laor, A., Izrae li, S., & Pandolf, K. B. (1999). Can gender differences during exercise-h eat stress be assessed by the physiological strain index? The American Journal of Physiology 276 R1798–R1804. 46 Morimoto, T., Slabochova, Z., Naman, R. K., & Sargent, F., II. (1967). Gender differences in physiological reactions to thermal stress. Journal of Applied Physiology 22 526–532.

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43 47 McLellan, T. M. (1998). Sex-related differe nces in thermoregulatory responses while wearing protective clothing. European Journal of Applied Physiology 78 28–37. 48 Yousef, M. K., Dill, D. B., Vitez, T. S ., Hillyard, S. D., & Goldman, A. S. (1984). Thermoregulatory responses to desert heat: Age, race, and gender. Journal of Gerontology 39 406–414. 49 Kamon, E., Avellini, B., & Krajewski, J. (1978). Physiological and biophysical limits to work in the heat for clothed men and women. Journal of Applied Physiology 44 918– 925. 50 Kenney, W. L., & Zeman, M. J. (2002). Psyc hometric limits and critical evaporative coefficients for unacclimated men and women. Journal of Applied Physiology 92 2256– 2263. 51 Avellini, B. A., Kamon, E., & Krajewski, J. T. (1980). Physiological responses of physically fit men and women to acclimation to humid heat. Journal of Applied Physiology 49 254–261. 52 Kamon, E., & Avellini, B. (1976). Physio logic limits to work in the heat and evaporative coefficient for women. Journal of Applied Physiology 41 71–76. 53 Moran, D. S., Avraham, S., & Pandolf, K. B. (1998). A physiological strain index to evaluate heat stress. American Journal of Physiology —Regulatory, Integrative, and Comparative Physiology 275 R129–R134. 54 Consolazio, C. R., Johnson, R. E., & Pecora, L. J. (1963). Physiological measurements of metabolic functions in man New York: McGraw-Hill. 55 Cortes-Vizcaino, C., & Bernard, T. E. (2000). Effects on heat stress of a flameretardant ensemble for aluminum smelters. American Industrial Hygiene Association Journal 61 873–876. 56 Kenney, W. L., & Zeman, M. J. (2002). Psyc hometric limits and critical evaporative coefficients for unacclimated men and women. Journal of Applied Physiology 92 2256– 2263. 57 Bernard, T. E., Luecke, C. L., Schwartz, S. W., Kirkland, K. S., & Ashley, C. D. (2005). WBGT clothing adjustments for four clothing ensembles under three relative humidity levels. Journal of Occupational Environmental Hygiene 2 251–256.

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44 APPENDIX A PARTICIPANT DATA

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45 Table A1 Participant Charac teristics—Main Study Subject Code Age Height (cm) Weight (kg) BSA (m2) Women (n=9) S1 26 163 52.0 1.55 S4 23 152 62.7 1.72 S5 27 170 91.4 2.36 S7 39 155 46.0 1.42 SS1 27 163 52.0 1.55 SS3 27 170 91.0 2.02 SS11 18 170 56.8 1.66 SS12 20 157 56.8 1.57 S13 44 163 65.0 1.82 Men (n=20) S0 26 180 92.7 2.14 S2 24 183 86.0 2.08 S3 25 183 77.0 1.99 S6 35 189 101.0 2.28 S8 20 183 130.0 2.48 S9 30 191 110.0 2.38 S10 32 173 71.0 1.84 S11 43 178 112.0 2.28 S12 28 185 95.0 2.19 SS2 28 185 95.0 2.19 SS4 26 180 95.0 2.15 SS5 27 175 97.7 2.13 SS6 20 180 82.7 2.03 SS7 20 183 71.8 1.93 SS8 24 163 63.6 1.68 SS9 43 149 75.0 1.69 SS10 49 175 86.0 2.02 SS13 21 185 81.8 2.06 SS15 22 178 63.6 1.80 SS16 33 186 86.4 2.11 Mean 29 174 80.9 1.97 Std Dev 8 12 20.19 0.28

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46 Appendix A (Continued) Table A2 Participant Characteristics—Subset Subject Code Age Height (cm) Weight (kg) BSA (m2) Women (n=4) SS1 27 163 52.0 1.55 SS3 27 170 91.0 2.02 SS11 18 170 56.8 1.66 SS12 20 157 56.8 1.57 Men (n=11) SS2 28 185 95.0 2.19 SS4 26 180 95.0 2.15 SS5 27 175 97.7 2.13 SS6 20 180 82.7 2.03 SS7 20 183 71.8 1.93 SS8 24 163 63.6 1.68 SS9 43 149 75.0 1.69 SS10 49 175 86.0 2.02 SS13 21 185 81.8 2.06 SS15 22 178 63.6 1.80 SS16 33 186 86.4 2.11 Mean 27 173 77.0 1.91 Std Dev 9 11 15.42 0.22

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47 APPENDIX B EXPERIMENTAL DATA

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48 Experimental Data: Data Dictionary Title Description ID Participant identification Gender Participant gender Ensemble Clothing worn: WC: Work Clothes CC: Cotton Coveralls TYV: Particle Barrier NG: Liquid Barrier TYCHEM: Vapor Barrier ML Metabolic Demand: M1: 80W/m2 M2: 160 W/m2 M3: 240 W/m2 MR Calculated metabolic rate based on O2 consumption (Watts) MSA MR divided by body surface area (W/m2) HR Heart rate in beats per minute (bpm) Tre Body core temperature (rectal) (C) Tsk Average skin temperature at four sites (C) WBGTcrit Calculated wet bulb globe temperat ure at the critical condition (C) PSI Physiological Strain Index

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49Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI S0 M CC R5 M2 319 149 96 37.80 35.55 33.8 3.17 S0 M NG R5 M2 308 144 93 37.70 34.67 31.4 2.86 S0 M NG R5 M2 325 152 95 37.70 35.55 33.2 2.95 S0 M TYCHEM R5 M2 448 209 95 37.42 35.53 24.9 2.49 S0 M TYV R5 M2 532 249 110 37.95 35.89 31.9 4.08 S0 M WC R5 M2 365 171 103 38.00 36.39 35.8 3.83 S1 F CC R5 M2 180 116 101 38.00 36.51 35.0 3.74 S1 F NG R5 M2 209 135 114 38.00 36.34 33.4 4.36 S1 F TYCHEM R5 M2 166 107 158 38.20 36.60 30.3 6.79 S1 F TYV R5 M2 186 120 139 37.90 37.20 35.0 5.38 S1 F WC R5 M2 198 128 126 38.00 35.66 34.1 4.93 S10 M CC R5 M2 326 177 135 38.07 36.61 33.1 5.47 S10 M NG R5 M2 320 174 129 37.80 36.70 30.9 4.74 S10 M TYCHEM R5 M2 329 179 128 37.82 36.16 26.3 4.72 S10 M TYCHEM R5 M2 337 183 146 38.33 36.80 27.4 6.43 S10 M TYV R5 M2 281 153 131 37.79 36.93 32.7 4.82 S10 M WC R5 M2 320 174 131 37.66 36.82 33.3 4.60 S11 M CC R5 M2 445 195 110 37.67 37.58 36.7 3.62 S11 M NG R5 M2 394 173 112 37.36 36.19 33.3 3.20 S11 M TYCHEM R5 M2 415 182 117 37.89 36.83 26.4 4.32 S11 M TYV R5 M2 459 201 110 37.68 35.98 35.1 3.63 S11 M WC R5 M2 427 187 115 37.76 37.00 36.5 4.00 S12 M CC R5 M2 304 139 103 37.62 36.71 36.7 3.20 S12 M CC R5 M2 151 69 122 37.49 35.37 34.7 3.89 S12 M NG R5 M2 316 144 105 37.82 36.58 32.3 3.63 S12 M TYCHEM R5 M2 325 148 99 37.58 36.05 26.0 2.94 S12 M TYV R5 M2 310 142 110 37.54 36.59 34.3 3.40

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50Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI S12 M WC R5 M2 323 147 119 37.84 36.81 35.3 4.33 S13 F CC R5 M2 289 159 128 38.31 37.29 38.2 5.54 S13 F NG R5 M2 332 182 123 38.12 36.60 32.1 4.99 S13 F TYCHEM R5 M2 310 170 123 38.25 36.51 29.0 5.20 S13 F TYV R5 M2 305 168 122 38.16 37.10 34.2 5.00 S13 F WC R5 M2 263 145 122 38.41 37.32 36.9 5.42 S2 M CC R5 M2 263 126 109 37.70 36.00 35.1 3.62 S2 M NG R5 M2 252 121 109 37.20 35.58 30.1 2.79 S2 M TYCHEM R5 M2 306 147 100 37.50 35.52 25.0 2.86 S2 M TYV R5 M2 306 147 114 37.80 37.21 34.2 4.02 S2 M WC R5 M2 281 135 112 37.50 35.69 34.1 3.43 S3 M CC R5 M2 283 142 111 37.90 36.29 35.9 4.05 S3 M NG R5 M2 206 104 132 38.00 36.25 34.2 5.21 S3 M NG R5 M2 244 123 106 38.11 36.34 33.2 4.16 S3 M TYCHEM R5 M2 293 147 93 37.50 34.15 25.1 2.52 S3 M TYV R5 M2 283 142 105 38.20 35.67 32.8 4.26 S3 M WC R5 M2 285 143 113 38.10 35.81 34.4 4.48 S4 F CC R5 M2 166 97 124 38.00 36.81 35.1 4.83 S4 F NG R5 M2 157 91 127 37.71 36.32 30.8 4.49 S4 F TYCHEM R5 M2 192 112 130 37.70 36.19 28.1 4.62 S4 F TYV R5 M2 118 69 110 37.47 35.80 32.7 3.28 S4 F WC R5 M2 184 107 136 38.00 36.07 34.2 5.40 S5 F CC R5 M2 293 124 113 37.33 36.18 33.9 3.19 S5 F NG R5 M2 274 116 117 37.51 36.74 32.9 3.68 S5 F TYCHEM R5 M2 275 117 107 37.33 36.00 27.0 2.91 S5 F TYV R5 M2 280 119 121 37.73 36.83 34.9 4.24

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51Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI S5 F WC R5 M2 242 103 108 37.50 36.37 34.1 3.24 S6 M CC R5 M2 310 136 96 37.72 36.51 37.4 3.03 S6 M NG R5 M2 358 157 88 37.60 35.83 31.3 2.45 S6 M TYCHEM R5 M2 408 179 85 37.48 35.49 28.4 2.11 S6 M TYV R5 M2 357 157 91 37.47 36.22 33.8 2.38 S6 M WC R5 M2 299 131 96 37.50 36.09 35.6 2.67 S7 F CC R5 M2 284 200 143 38.15 36.57 37.5 5.99 S7 F NG R5 M2 275 194 134 37.93 36.84 35.6 5.19 S7 F TYCHEM R5 M2 264 186 113 37.64 36.76 28.4 3.71 S7 F TYV R5 M2 257 181 118 37.81 36.69 34.9 4.23 S7 F WC R5 M2 296 208 136 37.91 36.40 35.1 5.25 S8 F CC R5 M2 425 171 146 37.47 36.83 37.7 5.00 S8 F NG R5 M2 432 174 129 37.55 35.84 35.8 4.32 S8 M TYCHEM R5 M2 430 173 103 37.52 35.16 25.8 3.03 S8 F TYV R5 M2 422 170 109 37.11 35.53 34.7 2.64 S8 M WC R5 M2 430 173 146 37.56 36.49 41.3 5.15 S9 M CC R5 M2 351 147 102 37.39 36.53 35.1 2.77 S9 M NG R5 M2 340 143 97 38.17 36.52 33.0 3.83 S9 M TYCHEM R5 M2 365 153 89 37.54 36.38 26.2 2.40 S9 M TYV R5 M2 376 158 105 37.96 36.98 36.4 3.86 S9 M WC R5 M2 356 150 108 37.67 36.50 35.1 3.52 SS1 F CC R5 M2 250 161 136 37.81 35.51 35.4 5.09 SS1 F NG R5 M2 297 192 111 37.28 35.63 31.7 3.01 SS1 F TYCHEM R5 M2 279 180 141 38.17 35.35 23.9 5.93 SS1 F TYV R5 M2 257 166 119 37.56 34.69 33.1 3.86 SS1 F WC R5 M2 170 110 86 37.01 36.34 38.0 1.37 SS1 F WC R5 M2 254 164 120 37.80 36.73 33.2 4.31

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52Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS10 M CC R5 M2 410 243 116 37.71 36.51 31.9 3.97 SS10 M NG R5 M2 372 220 110 37.59 36.91 31.1 3.48 SS10 M TYV R5 M2 345 204 101 37.84 35.91 32.4 3.47 SS10 M WC R5 M2 385 228 109 37.64 36.01 32.7 3.52 SS11 F CC R5 M2 260 157 116 37.57 37.30 35.1 3.74 SS11 F NG R5 M2 301 181 119 37.90 37.02 32.7 4.43 SS11 F TYCHEM R5 M2 231 139 119 37.72 37.28 28.6 4.13 SS11 F TYV R5 M2 260 157 119 37.39 36.07 33.8 3.58 SS11 F WC R5 M2 295 178 119 37.38 35.95 33.6 3.56 SS12 F CC R5 M2 307 196 149 37.93 36.53 34.3 5.91 SS12 F NG R5 M2 290 185 165 38.26 36.12 32.7 7.22 SS12 F TYCHEM R5 M2 306 195 154 38.08 37.87 26.0 6.40 SS12 F TYV R5 M2 299 190 156 38.21 36.60 34.3 6.71 SS13 M CC R5 M2 354 172 132 38.10 37.00 34.8 5.38 SS13 M NG R5 M2 356 173 125 37.66 35.85 30.8 4.31 SS13 M TYCHEM R5 M2 354 172 136 38.05 36.70 27.6 5.49 SS13 M TYV R5 M2 335 163 137 37.86 36.60 35.1 5.22 SS13 M WC R5 M2 476 231 156 37.91 37.46 37.6 6.21 SS15 M CC R5 M2 318 177 118 37.82 36.21 34.0 4.25 SS15 M NG R5 M2 332 184 110 37.56 36.14 32.1 3.43 SS15 M TYCHEM R5 M2 301 167 116 37.31 36.34 29.8 3.30 SS15 M TYV R5 M2 298 166 116 37.84 36.52 35.7 4.19 SS15 M WC R5 M2 285 158 118 37.68 36.55 34.7 4.01 SS16 M CC R5 M2 341 162 110 37.53 36.28 34.1 3.38 SS16 M NG R5 M2 340 161 101 37.72 36.25 32.8 3.27 SS16 M TYCHEM R5 M2 377 179 119 38.28 36.89 28.4 5.06 SS16 M TYV R5 M2 354 168 128 38.67 35.65 32.0 6.14

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53Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS16 M WC R5 M2 346 164 113 37.83 36.33 35.6 4.03 SS2 M CC R5 M2 385 176 113 37.46 36.10 34.5 3.41 SS2 M NG R5 M2 335 153 120 38.04 36.11 32.2 4.71 SS2 M TYCHEM R5 M2 310 142 101 37.36 36.50 29.2 2.67 SS2 M TYV R5 M2 399 182 117 37.74 36.79 37.1 4.07 SS2 M WC R5 M2 396 181 120 37.80 36.14 34.2 4.31 SS3 F CC R5 M2 318 157 116 37.63 36.02 33.2 3.84 SS3 F NG R5 M2 341 169 118 37.80 36.34 31.7 4.21 SS3 F TYCHEM R5 M2 275 136 117 37.65 35.85 29.6 3.92 SS3 F TYV R5 M2 328 162 113 37.61 36.12 33.5 3.66 SS3 F WC R5 M2 351 174 128 37.91 36.59 34.9 4.87 SS4 M CC R5 M2 411 203 93 37.74 36.02 33.7 2.92 SS4 M NG R5 M2 398 197 121 38.16 36.20 34.5 4.96 SS4 M TYCHEM R5 M2 464 230 95 37.78 35.17 25.7 3.09 SS4 M TYV R5 M2 444 220 95 37.76 35.19 33.3 3.05 SS4 M WC R5 M2 441 218 105 37.94 35.69 34.3 3.83 SS5 M CC R5 M2 406 201 106 37.45 35.73 34.3 3.06 SS5 M NG R5 M2 374 185 107 37.57 35.47 29.9 3.31 SS5 M TYCHEM R5 M2 356 176 115 37.47 36.72 29.0 3.52 SS5 M TYV R5 M2 377 187 110 37.81 36.42 33.6 3.85 SS5 M WC R5 M2 388 192 110 37.80 36.06 32.2 3.83 SS6 M CC R5 M2 347 163 85 37.16 36.02 33.7 1.58 SS6 M NG R5 M2 361 169 88 37.33 36.21 31.7 2.00 SS6 M TYCHEM R5 M2 341 160 90 37.28 36.00 27.2 2.01 SS6 M TYV R5 M2 323 152 90 37.20 36.04 34.9 1.88 SS6 M WC R5 M2 364 171 73 37.50 35.38 32.5 1.57 SS7 M CC R5 M2 339 176 116 37.71 36.41 35.8 3.97

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54Appendix B (Continued) Experimental Data – Main StudyID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS7 M NG R5 M2 339 176 110 37.66 36.66 33.1 3.60 SS7 M TYCHEM R5 M2 335 174 122 38.12 36.48 28.6 4.94 SS7 M TYV R5 M2 363 188 107 37.62 36.68 34.5 3.39 SS7 M WC R5 M2 343 178 103 37.70 36.19 33.9 3.33 SS8 M CC R5 M2 306 182 122 37.46 35.74 32.5 3.84 SS8 M NG R5 M2 270 161 119 37.39 35.64 29.9 3.58 SS8 M TYCHEM R5 M2 334 199 140 37.81 36.82 25.3 5.28 SS8 M TYV R5 M2 314 187 134 37.70 36.31 33.0 4.81 SS8 M WC R5 M2 276 164 130 38.03 36.32 32.4 5.17 SS9 M CC R5 M2 331 196 120 37.92 36.71 35.2 4.51 SS9 M NG R5 M2 339 201 114 37.88 36.38 32.5 4.16 SS9 M TYCHEM R5 M2 363 215 137 38.26 37.06 29.4 5.89 SS9 M TYV R5 M2 372 220 120 37.92 36.83 35.1 4.51 SS9 M WC R5 M2 359 212 117 37.86 36.16 34.1 4.27

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55Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS1 F CC R5 M1 114 74 86 37.81 37.08 38.1 2.71 SS1 F CC R5 M2 250 161 136 37.81 35.51 35.4 5.09 SS1 F CC R5 M3 309 199 150 37.71 33.21 30.2 5.59 SS1 F NG R5 M1 121 78 89 37.09 35.94 35.9 1.65 SS1 F NG R5 M2 297 192 111 37.28 35.63 31.7 3.01 SS1 F NG R5 M3 348 225 110 37.74 35.21 29.4 3.73 SS1 F TY1427 R5 M1 128 83 104 37.21 36.16 35.4 2.56 SS1 F TY1427 R5 M2 257 166 119 37.56 34.69 33.1 3.86 SS1 F TY1427 R5 M3 376 243 150 38.11 33.22 26.8 6.25 SS1 F TYCHEM R5 M1 116 75 108 37.65 36.98 32.8 3.49 SS1 F TYCHEM R5 M2 279 180 141 38.17 35.35 23.9 5.93 SS1 F TYCHEM R5 M3 385 248 172 38.34 33.63 24.3 7.69 SS1 F WC R5 M2 170 110 86 37.01 36.34 38.0 1.37 SS1 F WC R5 M2 254 164 120 37.80 36.73 33.2 4.31 SS1 F WC R5 M3 384 248 124 37.51 34.66 30.2 4.02 SS10 M CC R5 M1 224 133 99 37.57 36.88 38.7 2.93 SS10 M CC R5 M2 410 243 116 37.71 36.51 31.9 3.97 SS10 M CC R5 M3 534 316 122 37.91 35.68 29.6 4.59 SS10 M NG R5 M1 260 154 93 37.38 36.93 34.3 2.32 SS10 M NG R5 M2 372 220 110 37.59 36.91 31.1 3.48 SS10 M NG R5 M3 542 321 141 38.15 36.16 31.7 5.89 SS10 M TY1427 R5 M1 215 127 97 37.44 36.78 35.3 2.61 SS10 M TY1427 R5 M2 345 204 101 37.84 35.91 32.4 3.47 SS10 M TY1427 R5 M3 568 336 129 38.16 35.38 31.2 5.34 SS10 M TYCHEM R5 M1 235 139 104 37.54 37.25 33.2 3.11 SS10 M TYCHEM R5 M3 592 350 140 38.53 36.72 23.5 6.48 SS10 M WC R5 M1 231 137 108 37.76 36.93 37.5 3.67

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56Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS10 M WC R5 M2 385 228 109 37.64 36.01 32.7 3.52 SS10 M WC R5 M3 656 388 141 38.41 36.49 31.0 6.33 SS11 F CC R5 M1 165 99 97 37.39 36.91 35.7 2.53 SS11 F CC R5 M2 260 157 116 37.57 37.30 35.1 3.74 SS11 F CC R5 M3 371 223 136 37.78 35.09 30.3 5.04 SS11 F NG R5 M1 194 117 117 37.41 37.49 36.8 3.52 SS11 F NG R5 M2 301 181 119 37.90 37.02 32.7 4.43 SS11 F NG R5 M3 439 264 129 37.36 35.28 29.2 4.00 SS11 F TY1427 R5 M1 160 96 107 37.49 36.78 36.1 3.17 SS11 F TY1427 R5 M2 260 157 119 37.39 36.07 33.8 3.58 SS11 F TY1427 R5 M3 369 222 125 37.59 35.83 30.6 4.20 SS11 F TYCHEM R5 M1 167 101 93 37.20 36.48 29.6 2.02 SS11 F TYCHEM R5 M2 231 139 119 37.72 37.28 28.6 4.13 SS11 F TYCHEM R5 M3 351 211 115 37.27 36.38 25.6 3.19 SS11 F WC R5 M1 181 109 106 37.38 36.58 36.6 2.94 SS11 F WC R5 M2 295 178 119 37.38 35.95 33.6 3.56 SS11 F WC R5 M3 399 240 136 37.73 35.96 31.5 4.95 SS12 F CC R5 M1 170 108 135 37.68 37.38 36.9 4.82 SS12 F CC R5 M2 307 196 149 37.93 36.53 34.3 5.91 SS12 F CC R5 M3 365 232 171 38.06 35.67 33.0 7.17 SS12 F NG R5 M1 105 67 142 37.70 37.57 35.4 5.19 SS12 F NG R5 M2 290 185 165 38.26 36.12 32.7 7.22 SS12 F NG R5 M3 404 257 145 37.86 34.78 28.6 5.60 SS12 F TY1427 R5 M1 160 102 146 37.90 36.94 37.4 5.71 SS12 F TY1427 R5 M2 299 190 156 38.21 36.60 34.3 6.71 SS12 F TY1427 R5 M3 472 301 164 38.34 36.20 32.1 7.30 SS12 F TYCHEM R5 M1 152 97 151 37.98 37.58 34.2 6.09

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57Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS12 F TYCHEM R5 M1 174 111 164 38.01 37.50 29.6 6.75 SS12 F TYCHEM R5 M2 306 195 154 38.08 37.87 26.0 6.40 SS12 F TYCHEM R5 M3 384 245 149 38.06 34.86 23.6 6.12 SS12 F TYCHEM R5 M3 369 235 172 38.26 36.44 28.2 7.55 SS12 F WC R5 M1 157 100 135 37.70 36.83 36.6 4.86 SS12 F WC R5 M3 392 250 182 38.23 36.10 31.1 7.98 SS13 M CC R5 M1 209 101 126 37.54 36.15 36.0 4.16 SS13 M CC R5 M2 354 172 132 38.10 37.00 34.8 5.38 SS13 M CC R5 M3 441 214 144 37.98 34.97 32.4 5.75 SS13 M NG R5 M1 244 118 120 37.50 36.70 34.9 3.81 SS13 M NG R5 M2 356 173 125 37.66 35.85 30.8 4.31 SS13 M NG R5 M3 557 270 164 38.84 36.29 29.9 8.14 SS13 M TY1427 R5 M1 233 113 129 37.84 37.33 38.5 4.80 SS13 M TY1427 R5 M2 335 163 137 37.86 36.60 35.1 5.22 SS13 M TY1427 R5 M3 463 225 132 38.16 35.08 30.3 5.48 SS13 M TYCHEM R5 M1 211 102 110 37.31 36.96 31.2 3.02 SS13 M TYCHEM R5 M2 354 172 136 38.05 36.70 27.6 5.49 SS13 M TYCHEM R5 M3 507 246 138 38.53 34.75 24.1 6.38 SS13 M WC R5 M1 210 102 117 36.38 36.66 38.6 1.80 SS13 M WC R5 M2 476 231 156 37.91 37.46 37.6 6.21 SS13 M WC R5 M3 445 216 147 38.13 35.56 30.0 6.15 SS15 M CC R5 M1 221 123 109 37.15 36.30 37.1 2.70 SS15 M CC R5 M2 318 177 118 37.82 36.21 34.0 4.25 SS15 M CC R5 M3 467 259 135 38.19 35.59 32.9 5.67 SS15 M NG R5 M1 223 124 112 37.62 36.68 35.0 3.63 SS15 M NG R5 M2 332 184 110 37.56 36.14 32.1 3.43 SS15 M NG R5 M3 466 259 128 37.73 35.81 29.4 4.57

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58Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS15 M TY1427 R5 M1 222 123 99 37.39 36.71 34.1 2.63 SS15 M TY1427 R5 M2 298 166 116 37.84 36.52 35.7 4.19 SS15 M TY1427 R5 M3 484 269 135 37.83 35.83 38.9 5.07 SS15 M TYCHEM R5 M1 188 104 103 37.31 37.02 31.5 2.68 SS15 M TYCHEM R5 M2 301 167 116 37.31 36.34 29.8 3.30 SS15 M TYCHEM R5 M3 453 252 133 37.65 36.48 25.8 4.68 SS15 M WC R5 M1 211 117 113 37.44 36.64 37.7 3.38 SS15 M WC R5 M2 285 158 118 37.68 36.55 34.7 4.01 SS15 M WC R5 M3 476 264 116 37.78 35.62 30.3 4.09 SS16 M CC R5 M1 240 114 108 37.56 36.22 36.5 3.34 SS16 M CC R5 M2 341 162 110 37.53 36.28 34.1 3.38 SS16 M CC R5 M3 511 242 127 38.09 35.77 32.5 5.13 SS16 M NG R5 M1 204 97 121 37.79 36.45 34.9 4.34 SS16 M NG R5 M2 340 161 101 37.72 36.25 32.8 3.27 SS16 M NG R5 M3 468 222 135 37.90 36.15 30.1 5.19 SS16 M TY1427 R5 M1 192 91 122 37.71 36.56 37.1 4.25 SS16 M TY1427 R5 M2 354 168 128 38.67 35.65 32.0 6.14 SS16 M TY1427 R5 M3 450 213 124 37.75 36.04 33.1 4.42 SS16 M TYCHEM R5 M1 266 126 119 37.98 36.97 33.2 4.56 SS16 M TYCHEM R5 M1 204 97 116 37.43 37.11 39.0 3.50 SS16 M TYCHEM R5 M2 377 179 119 38.28 36.89 28.4 5.06 SS16 M TYCHEM R5 M3 467 221 139 37.85 36.42 28.9 5.30 SS16 M TYCHEM R5 M3 485 230 136 37.83 36.43 28.0 5.12 SS16 M WC R5 M1 223 106 109 37.34 36.35 37.9 3.02 SS16 M WC R5 M2 346 164 113 37.83 36.33 35.6 4.03 SS16 M WC R5 M3 469 222 126 38.02 35.97 34.5 4.96 SS2 M CC R5 M2 385 176 113 37.46 36.10 34.5 3.41

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59Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS2 M NG R5 M1 235 107 127 37.53 36.81 36.1 4.19 SS2 M NG R5 M2 335 153 120 38.04 36.11 32.2 4.71 SS2 M NG R5 M3 474 216 127 38.29 35.57 35.1 5.46 SS2 M TY1427 R5 M1 191 87 111 37.63 36.83 35.9 3.60 SS2 M TY1427 R5 M2 399 182 117 37.74 36.79 37.1 4.07 SS2 M TY1427 R5 M3 459 210 122 38.24 35.67 32.7 5.14 SS2 M TYCHEM R5 M2 310 142 101 37.36 36.50 29.2 2.67 SS2 M TYCHEM R5 M3 478 218 126 38.05 36.08 25.4 5.01 SS2 M WC R5 M1 222 101 123 37.36 36.66 38.3 3.72 SS2 F WC R5 M1 249 123 106 37.57 36.89 38.8 3.26 SS2 M WC R5 M2 396 181 120 37.80 36.14 34.2 4.31 SS2 M WC R5 M3 506 231 131 38.33 36.30 35.1 5.72 SS3 F CC R5 M1 240 119 116 37.51 36.50 36.5 3.64 SS3 F CC R5 M2 318 157 116 37.63 36.02 33.2 3.84 SS3 F CC R5 M3 503 249 142 38.07 36.01 30.1 5.81 SS3 F NG R5 M1 234 116 112 37.56 36.25 34.1 3.53 SS3 F NG R5 M2 341 169 118 37.80 36.34 31.7 4.21 SS3 F NG R5 M3 453 224 131 37.85 35.15 28.0 4.92 SS3 F TY1427 R5 M1 221 109 114 37.49 37.01 37.5 3.51 SS3 F TY1427 R5 M2 328 162 113 37.61 36.12 33.5 3.66 SS3 F TY1427 R5 M3 540 267 138 38.08 35.93 30.9 5.63 SS3 F TYCHEM R5 M1 232 115 136 38.05 37.18 30.9 5.49 SS3 F TYCHEM R5 M2 275 136 117 37.65 35.85 29.6 3.92 SS3 F TYCHEM R5 M3 442 219 138 38.42 36.08 25.6 6.20 SS3 F WC R5 M2 351 174 128 37.91 36.59 34.9 4.87 SS3 F WC R5 M3 505 250 140 38.10 35.82 30.2 5.76 SS4 M CC R5 M1 263 130 96 37.40 36.67 38.4 2.50

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60Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS4 M CC R5 M2 411 203 93 37.74 36.02 33.7 2.92 SS4 M CC R5 M3 282 140 100 37.84 33.95 28.2 3.42 SS4 M NG R5 M1 243 120 95 37.76 36.30 34.4 3.05 SS4 M NG R5 M2 398 197 121 38.16 36.20 34.5 4.96 SS4 M NG R5 M3 591 293 122 38.14 35.36 30.5 4.97 SS4 M TY1427 R5 M1 215 106 87 37.23 36.37 37.5 1.79 SS4 M TY1427 R5 M2 444 220 95 37.76 35.19 33.3 3.05 SS4 M TY1427 R5 M3 587 291 108 38.05 34.66 29.8 4.15 SS4 M TYCHEM R5 M1 257 127 90 37.72 36.66 30.4 2.75 SS4 M TYCHEM R5 M2 464 230 95 37.78 35.17 25.7 3.09 SS4 M TYCHEM R5 M3 561 278 111 37.77 35.38 23.3 3.83 SS4 M WC R5 M1 290 144 95 37.62 36.13 36.5 2.82 SS4 M WC R5 M2 441 218 105 37.94 35.69 34.3 3.83 SS4 M WC R5 M3 465 230 95 37.91 34.86 32.0 3.30 SS5 M CC R5 M1 289 143 102 37.19 36.30 35.2 2.44 SS5 M CC R5 M2 406 201 106 37.45 35.73 34.3 3.06 SS5 M CC R5 M3 476 236 110 37.88 35.45 32.1 3.97 SS5 M NG R5 M1 249 123 111 37.44 36.48 34.9 3.28 SS5 M NG R5 M2 374 185 107 37.57 35.47 29.9 3.31 SS5 M NG R5 M3 489 242 108 37.46 35.16 27.5 3.17 SS5 M TY1427 R5 M1 252 125 121 37.69 36.61 36.2 4.17 SS5 M TY1427 R5 M2 377 187 110 37.81 36.42 33.6 3.85 SS5 M TY1427 R5 M3 453 224 105 37.33 34.65 30.0 2.81 SS5 M TYCHEM R5 M1 272 135 113 37.17 36.46 28.6 2.93 SS5 M TYCHEM R5 M2 356 176 115 37.47 36.72 29.0 3.52 SS5 M TYCHEM R5 M3 525 260 130 37.50 35.74 23.5 4.29 SS5 M WC R5 M1 286 142 103 37.71 35.74 34.8 3.35

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61Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS5 M WC R5 M2 388 192 110 37.80 36.06 32.2 3.83 SS5 M WC R5 M3 477 236 112 37.51 34.52 30.9 3.45 SS6 M CC R5 M1 229 108 74 37.19 35.55 35.5 1.10 SS6 M CC R5 M2 347 163 85 37.16 36.02 33.7 1.58 SS6 M CC R5 M3 503 236 102 37.77 36.36 34.5 3.40 SS6 M NG R5 M1 251 118 78 37.37 36.76 35.1 1.59 SS6 M NG R5 M2 361 169 88 37.33 36.21 31.7 2.00 SS6 M NG R5 M3 578 271 103 37.79 35.68 30.2 3.48 SS6 M TY1427 R5 M1 227 107 73 37.04 36.26 35.4 0.80 SS6 M TY1427 R5 M2 323 152 90 37.20 36.04 34.9 1.88 SS6 M TY1427 R5 M3 415 195 93 37.85 35.65 38.1 3.11 SS6 M TYCHEM R5 M1 247 116 75 37.69 36.94 32.0 1.98 SS6 M TYCHEM R5 M2 341 160 90 37.28 36.00 27.2 2.01 SS6 M TYCHEM R5 M3 513 241 103 37.34 35.52 23.4 2.73 SS6 M WC R5 M1 241 113 82 37.59 36.24 36.5 2.15 SS6 M WC R5 M2 364 171 73 37.50 35.38 32.5 1.57 SS6 M WC R5 M3 511 240 91 37.53 35.78 32.8 2.48 SS7 M CC R5 M1 268 139 96 37.13 35.72 34.6 2.05 SS7 M CC R5 M2 339 176 116 37.71 36.41 35.8 3.97 SS7 M CC R5 M3 636 330 105 37.52 35.66 31.4 3.13 SS7 M NG R5 M1 202 105 107 37.84 36.73 34.9 3.76 SS7 M NG R5 M2 339 176 110 37.66 36.66 33.1 3.60 SS7 M NG R5 M3 592 307 109 37.62 35.06 28.7 3.49 SS7 M TY1427 R5 M1 220 114 112 37.43 36.04 36.1 3.31 SS7 M TY1427 R5 M2 363 188 107 37.62 36.68 34.5 3.39 SS7 M TYCHEM R5 M1 221 115 106 37.43 36.29 31.8 3.03 SS7 M TYCHEM R5 M2 335 174 122 38.12 36.48 28.6 4.94

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62Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS7 M TYCHEM R5 M3 497 258 113 37.96 35.13 21.6 4.24 SS7 M WC R5 M1 230 119 100 37.22 35.58 35.7 2.39 SS7 M WC R5 M2 343 178 103 37.70 36.19 33.9 3.33 SS7 M WC R5 M3 507 263 109 37.97 35.68 32.0 4.07 SS8 M CC R5 M1 171 102 115 37.10 36.07 34.4 2.90 SS8 M CC R5 M2 306 182 122 37.46 35.74 32.5 3.84 SS8 M CC R5 M3 447 266 146 37.92 35.89 30.6 5.75 SS8 M NG R5 M1 172 102 109 37.42 36.61 33.0 3.15 SS8 M NG R5 M2 270 161 119 37.39 35.64 29.9 3.58 SS8 M NG R5 M3 408 243 161 38.20 36.40 27.9 6.93 SS8 M TY1427 R5 M1 171 102 101 36.74 35.75 31.6 1.64 SS8 M TY1427 R5 M2 314 187 134 37.70 36.31 33.0 4.81 SS8 M TY1427 R5 M3 404 240 145 37.69 35.80 31.1 5.32 SS8 M TYCHEM R5 M2 334 199 140 37.81 36.82 25.3 5.28 SS8 M TYCHEM R5 M3 360 214 135 38.00 35.74 24.4 5.36 SS8 M WC R5 M1 176 105 118 37.40 36.89 35.3 3.55 SS8 M WC R5 M2 276 164 130 38.03 36.32 32.4 5.17 SS8 M WC R5 M3 416 248 159 38.12 36.48 31.2 6.70 SS9 M CC R5 M2 331 196 120 37.92 36.71 35.2 4.51 SS9 M CC R5 M3 487 288 123 37.91 36.18 33.3 4.64 SS9 M NG R5 M1 252 149 132 38.11 37.26 34.9 5.40 SS9 M NG R5 M2 339 201 114 37.88 36.38 32.5 4.16 SS9 M NG R5 M3 527 312 130 38.04 35.69 29.6 5.19 SS9 M TY1427 R5 M1 243 144 142 37.96 37.07 37.7 5.62 SS9 M TY1427 R5 M2 372 220 120 37.92 36.83 35.1 4.51 SS9 M TY1427 R5 M3 520 308 139 38.24 36.73 34.1 5.95 SS9 M TYCHEM R5 M1 278 164 133 38.13 37.02 29.9 5.48

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63Appendix B (Continued) Experimental Data – Subset ID GENDER Ensemble RHL ML MR MSA HR Tre Tsk WBGTcrit PSI SS9 M TYCHEM R5 M2 363 215 137 38.26 37.06 29.4 5.89 SS9 M TYCHEM R5 M3 634 375 139 38.33 36.26 25.3 6.10 SS9 M WC R5 M1 343 203 119 37.91 36.40 36.4 4.45 SS9 M WC R5 M2 359 212 117 37.86 36.16 34.1 4.27 SS9 M WC R5 M3 520 308 133 38.15 35.95 30.1 5.51

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64 APPENDIX C DATA ANALYSIS

PAGE 73

65 GENDER=F, Ensemble=CC Distributions HR 100 110 120 130 140 150 Moments Mean 127.2 Std Dev 16.005555 Std Err Mean 5.0614008 upper 95% Mean 138.64968 lower 95% Mean 115.75032 N 10 Tre 37.25 37.5 37.75 38 38.25 38.5

PAGE 74

66 Moments Mean 37.82 Std Dev 0.313971 Std Err Mean 0.0992863 upper 95% Mean 38.044601 lower 95% Mean 37.595399 N 10 Tsk 35.5 36 36.5 37 37.5 Moments Mean 36.553 Std Dev 0.5518718 Std Err Mean 0.1745172 upper 95% Mean 36.947785 lower 95% Mean 36.158215 N 10

PAGE 75

67 PSI 3 3.5 4 4.5 5 5.5 6 Moments Mean 4.6857143 Std Dev 0.9972904 Std Err Mean 0.3153709 upper 95% Mean 5.3991328 lower 95% Mean 3.9722957 N 10 GENDER=F, Ensemble=NG Distributions HR 110 120 130 140 150 160 170

PAGE 76

68 Moments Mean 125.7 Std Dev 15.513793 Std Err Mean 4.9058921 upper 95% Mean 136.7979 lower 95% Mean 114.6021 N 10 Tre 37.25 37.5 37.75 38 38.25 38.5 Moments Mean 37.806 Std Dev 0.2991915 Std Err Mean 0.0946127 upper 95% Mean 38.020029 lower 95% Mean 37.591971 N 10

PAGE 77

69 Tsk 35.5 36 36.5 37 Moments Mean 36.3776 Std Dev 0.4368196 Std Err Mean 0.1381345 upper 95% Mean 36.690082 lower 95% Mean 36.065118 N 10 PSI 3 4 5 6 7 8

PAGE 78

70 Moments Mean 4.5909524 Std Dev 1.1075418 Std Err Mean 0.3502355 upper 95% Mean 5.38324 lower 95% Mean 3.7986647 N 10 GENDER=F, Ensemble=TYCHEM Distributions HR 100 110 120 130 140 150 160 Moments Mean 129.11111 Std Dev 18.134528 Std Err Mean 6.0448427 upper 95% Mean 143.05054 lower 95% Mean 115.17168 N 9

PAGE 79

71 Tre 37.25 37.5 37.75 38 38.25 38.5 Moments Mean 37.86 Std Dev 0.3222577 Std Err Mean 0.1074192 upper 95% Mean 38.107709 lower 95% Mean 37.612291 N 9 Tsk 35 35.5 36 36.5 37 37.5 38

PAGE 80

72 Moments Mean 36.489667 Std Dev 0.7606517 Std Err Mean 0.2535506 upper 95% Mean 37.074355 lower 95% Mean 35.904978 N 9 PSI 2 3 4 5 6 7 Moments Mean 4.8433862 Std Dev 1.319896 Std Err Mean 0.4399653 upper 95% Mean 5.8579481 lower 95% Mean 3.8288243 N 9

PAGE 81

73 GENDER=F, Ensemble=TYV Distributions HR 100 110 120 130 140 150 160 Moments Mean 122.6 Std Dev 14.41604 Std Err Mean 4.5587523 upper 95% Mean 132.91261 lower 95% Mean 112.28739 N 10 Tre 37 37.25 37.5 37.75 38 38.25

PAGE 82

74 Moments Mean 37.695 Std Dev 0.341443 Std Err Mean 0.1079738 upper 95% Mean 37.939254 lower 95% Mean 37.450746 N 10 Tsk 34.5 35 35.5 36 36.5 37 37.5 Moments Mean 36.2621 Std Dev 0.7794683 Std Err Mean 0.2464895 upper 95% Mean 36.819698 lower 95% Mean 35.704502 N 10

PAGE 83

75 PSI 2 3 4 5 6 7 Moments Mean 4.2583333 Std Dev 1.1726744 Std Err Mean 0.3708322 upper 95% Mean 5.0972141 lower 95% Mean 3.4194526 N 10 GENDER=F, Ensemble=WC Distributions HR 80 90 100 110 120 130 140

PAGE 84

76 Moments Mean 120.11111 Std Dev 15.479377 Std Err Mean 5.1597923 upper 95% Mean 132.00961 lower 95% Mean 108.21261 N 9 Tre 37 37.25 37.5 37.75 38 38.25 38.5 Moments Mean 37.768889 Std Dev 0.4120208 Std Err Mean 0.1373403 upper 95% Mean 38.085596 lower 95% Mean 37.452182 N 9

PAGE 85

77 Tsk 35.5 36 36.5 37 37.5 Moments Mean 36.380778 Std Dev 0.4811327 Std Err Mean 0.1603776 upper 95% Mean 36.750609 lower 95% Mean 36.010946 N 9 PSI 1 2 3 4 5 6

PAGE 86

78 Moments Mean 4.262963 Std Dev 1.338693 Std Err Mean 0.446231 upper 95% Mean 5.2919735 lower 95% Mean 3.2339524 N 9 GENDER=M, Ensemble=CC Distributions HR 80 90 100 110 120 130 140 Moments Mean 110.75 Std Dev 12.706712 Std Err Mean 2.8413071 upper 95% Mean 116.69692 lower 95% Mean 104.80308 N 20

PAGE 87

79 Tre 37 37.2 37.4 37.6 37.8 38 38.2 Moments Mean 37.671 Std Dev 0.2340468 Std Err Mean 0.0523345 upper 95% Mean 37.780537 lower 95% Mean 37.561463 N 20 Tsk 35 35.5 36 36.5 37 37.5 38

PAGE 88

80 Moments Mean 36.2933 Std Dev 0.5158137 Std Err Mean 0.1153395 upper 95% Mean 36.534708 lower 95% Mean 36.051892 N 20 PSI 1.5 2 2.5 3 3.5 4 4.5 5 5.5 Moments Mean 3.6540476 Std Dev 0.8817449 Std Err Mean 0.1971642 upper 95% Mean 4.0667169 lower 95% Mean 3.2413783 N 20

PAGE 89

81 GENDER=M, Ensemble=NG Distributions HR 80 90 100 110 120 130 140 Moments Mean 109.09524 Std Dev 12.565448 Std Err Mean 2.7420055 upper 95% Mean 114.81496 lower 95% Mean 103.37551 N 21 Tre 37 37.2 37.4 37.6 37.8 38 38.2

PAGE 90

82 Moments Mean 37.715238 Std Dev 0.2755834 Std Err Mean 0.0601372 upper 95% Mean 37.840682 lower 95% Mean 37.589794 N 21 Tsk 34.5 35 35.5 36 36.5 37 Moments Mean 36.095524 Std Dev 0.5160604 Std Err Mean 0.1126136 upper 95% Mean 36.330432 lower 95% Mean 35.860616 N 21

PAGE 91

83 PSI 1.5 2 2.5 3 3.5 4 4.5 5 5.5 Moments Mean 3.6489796 Std Dev 0.8370975 Std Err Mean 0.1826696 upper 95% Mean 4.0300218 lower 95% Mean 3.2679374 N 21 GENDER=M, Ensemble=TYCHEM Distributions HR 80 90 100 110 120 130 140 150

PAGE 92

84 Moments Mean 111.3 Std Dev 18.893329 Std Err Mean 4.2246769 upper 95% Mean 120.14235 lower 95% Mean 102.45765 N 20 Tre 37.25 37.5 37.75 38 38.25 38.5 Moments Mean 37.715 Std Dev 0.3392329 Std Err Mean 0.0758548 upper 95% Mean 37.873766 lower 95% Mean 37.556234 N 20

PAGE 93

85 Tsk 34 34.5 35 35.5 36 36.5 37 37.5 Moments Mean 36.1371 Std Dev 0.7555119 Std Err Mean 0.1689376 upper 95% Mean 36.49069 lower 95% Mean 35.78351 N 20 PSI 2 3 4 5 6 7

PAGE 94

86 Moments Mean 3.7535714 Std Dev 1.3756515 Std Err Mean 0.307605 upper 95% Mean 4.3973961 lower 95% Mean 3.1097467 N 20 GENDER=M, Ensemble=TYV Distributions HR 80 90 100 110 120 130 140 Moments Mean 112.15789 Std Dev 13.557545 Std Err Mean 3.1103141 upper 95% Mean 118.69242 lower 95% Mean 105.62337 N 19

PAGE 95

87 Tre 37 37.5 38 38.5 Moments Mean 37.807895 Std Dev 0.2966213 Std Err Mean 0.0680496 upper 95% Mean 37.950862 lower 95% Mean 37.664928 N 19 Tsk 35 35.5 36 36.5 37 37.5

PAGE 96

88 Moments Mean 36.337316 Std Dev 0.5329635 Std Err Mean 0.1222702 upper 95% Mean 36.594196 lower 95% Mean 36.080436 N 19 PSI 1 2 3 4 5 6 7 Moments Mean 3.9492481 Std Dev 0.969536 Std Err Mean 0.2224268 upper 95% Mean 4.4165495 lower 95% Mean 3.4819467 N 19

PAGE 97

89 GENDER=M, Ensemble=WC Distributions HR 60 80 100 120 140 160 Moments Mean 114.85 Std Dev 17.496691 Std Err Mean 3.9123791 upper 95% Mean 123.0387 lower 95% Mean 106.6613 N 20 Tre 37.4 37.5 37.6 37.7 37.8 37.9 38 38.1 38.2

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90 Moments Mean 37.764 Std Dev 0.1792499 Std Err Mean 0.0400815 upper 95% Mean 37.847892 lower 95% Mean 37.680108 N 20 Tsk 35 35.5 36 36.5 37 37.5 Moments Mean 36.2933 Std Dev 0.4920157 Std Err Mean 0.1100181 upper 95% Mean 36.52357 lower 95% Mean 36.06303 N 20

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91 PSI 1 2 3 4 5 6 7 Moments Mean 4.0042857 Std Dev 0.9572263 Std Err Mean 0.2140423 upper 95% Mean 4.4522814 lower 95% Mean 3.55629 N 20

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92 Least Squares Fit Response MR Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 171798.09 141.6154 <.0001 Ensemble 4 4 5218.17 1.0754 0.3721 ID[GENDER] 28 28 400153.85 11.7804 <.0001 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 277.21045 5.1143628 269.646 M 351.54755 3.5785060 347.430 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 307.89104 6.4959604 315.733 NG 306.58908 6.4180577 315.710 TYCHEM 320.47817 6.6641313 327.207 TYV 319.98621 6.5763847 328.966 WC 316.95048 6.6773862 324.069 ID[GENDER] Response MSA Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 11065.93 36.0548 <.0001 Ensemble 4 4 999.30 0.8140 0.5188 ID[GENDER] 28 28 106323.97 12.3722 <.0001 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 153.90953 2.5724696 152.395 M 172.77598 1.7999501 171.521 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 160.45285 3.2673983 162.288 NG 159.99514 3.2282141 162.356 TYCHEM 166.31736 3.3519865 167.447 TYV 165.46301 3.3078509 168.440

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93 Level Least Sq Mean Std Error Mean WC 164.48540 3.3586536 166.367 ID[GENDER]

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94 Response WBGT Whole Model Summary of Fit RSquare 0.851683 RSquare Adj 0.808749 Root Mean Square Error 1.417156 Mean of Response 32.71224 Observations (or Sum Wgts) 148 Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Model 33 1314.6997 39.8394 19.8371 Error 114 228.9497 2.0083 Prob > F C. Total 147 1543.6494 <.0001 Lack Of Fit Source DF Sum of Squares Mean Square F Ratio Lack Of Fit 109 212.77956 1.95211 0.6036 Pure Error 5 16.17011 3.23402 Prob > F Total Error 114 228.94968 0.8488 Max RSq 0.9895 Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 9.1983 4.5801 0.0345 Ensemble 4 4 1165.7700 145.1168 <.0001 ID[GENDER] 28 28 125.5953 2.2335 0.0016 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 33.143711 0.20809193 33.1341 M 32.599773 0.14560137 32.5098 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 35.110741 0.26430603 34.9427 NG 32.542649 0.26113634 32.3418 TYCHEM 27.456306 0.27114852 27.3203 TYV 34.267264 0.26757831 34.0945 WC 34.981749 0.27168784 34.8105 ID[GENDER]

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95 Least Squares Fit Response Tre Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 0.1091280 2.1312 0.1472 Ensemble 4 4 0.0148255 0.0724 0.9903 ID[GENDER] 28 28 6.2388656 4.3515 <.0001 GENDER*Ensemble 4 4 0.2808914 1.3714 0.2485 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 37.783761 0.03333006 37.7890 M 37.724429 0.02325649 37.7337 Power Details Test GENDER Power Alpha Sigma Delta Number Power 0.0500 0.226284 0.027154 148 0.3044 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 37.742306 0.04406991 37.7207 NG 37.749053 0.04376613 37.7445 TYCHEM 37.759812 0.04608021 37.7600 TYV 37.746346 0.04439274 37.7690 WC 37.772957 0.04667123 37.7655 Power Details Test Ensemble Power Alpha Sigma Delta Number Power 0.0500 0.226284 0.010009 148 0.0641 ID[GENDER] GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 37.820000 0.07155743 F,NG 37.806000 0.07155743

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96 Level Least Sq Mean Std Error F,TYCHEM 37.815889 0.07667499 F,TYV 37.695000 0.07155743 F,WC 37.781915 0.07843840 M,CC 37.664613 0.05146030 M,NG 37.692106 0.05041260 M,TYCHEM 37.703736 0.05113206 M,TYV 37.797691 0.05255849 M,WC 37.764000 0.05059875 Response HR Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 6059.321 57.8534 <.0001 Ensemble 4 4 92.493 0.2208 0.9263 ID[GENDER] 28 28 21501.783 7.3320 <.0001 GENDER*Ensemble 4 4 439.719 1.0496 0.3851 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 125.88340 1.5074011 124.958 M 111.90266 1.0518089 111.600 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 119.33038 1.9931266 116.233 NG 118.03283 1.9793876 114.452 TYCHEM 119.73528 2.0840450 116.828 TYV 117.69612 2.0077268 115.759 WC 119.67055 2.1107751 116.483 Power Details Test Ensemble Power Details Test Ensemble Power Alpha Sigma Delta Number Power 0.0500 10.23405 0.790538 148 0.0962 ID[GENDER]

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97 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 127.20000 3.2362901 F,NG 125.70000 3.2362901 F,TYCHEM 129.42593 3.4677391 F,TYV 122.60000 3.2362901 F,WC 124.49110 3.5474921 M,CC 111.46075 2.3273679 M,NG 110.36567 2.2799839 M,TYCHEM 110.04462 2.3125225 M,TYV 112.79225 2.3770348 M,WC 114.85000 2.2884027 Response Tsk Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 1.203569 4.6204 0.0338 Ensemble 4 4 0.475687 0.4565 0.7674 ID[GENDER] 28 28 18.692422 2.5628 0.0003 GENDER*Ensemble 4 4 0.6045770.5802 0.6776 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 36.422108 0.07517557 36.4117 M 36.225068 0.05245474 36.2289 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 36.410652 0.09939918 36.3799 NG 36.252987 0.09871399 36.1865 TYCHEM 36.285505 0.10393336 36.2465 TYV 36.289676 0.10012730 36.3114 WC 36.379119 0.10526642 36.3204 Power Details Test Ensemble Power Alpha Sigma Delta Number Power 0.0500 0.510382 0.056693 148 0.1542 ID[GENDER]

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98 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 36.553000 0.16139695 F,NG 36.377600 0.16139695 F,TYCHEM 36.452900 0.17293954 F,TYV 36.262100 0.16139695 F,WC 36.464938 0.17691690 M,CC 36.268303 0.11606811 M,NG 36.128375 0.11370503 M,TYCHEM 36.118109 0.11532776 M,TYV 36.317252 0.11854505 M,WC 36.293300 0.11412488 Response PSI Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F GENDER 1 1 18.124775 31.4221 <.0001 Ensemble 4 4 0.356015 0.1543 0.9607 ID[GENDER] 28 28 96.263605 5.9603 <.0001 GENDER*Ensemble 4 4 3.1879181.3817 0.2450 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 4.5626204 0.11186649 4.52723 M 3.7979845 0.07805631 3.79902 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 4.1814810 0.14791290 3.99794 NG 4.1309371 0.14689330 3.95284 TYCHEM 4.2299382 0.15466009 4.09179 TYV 4.1103914 0.14899640 4.05583 WC 4.2487644 0.15664377 4.08456 Power Details Test Ensemble Power Alpha Sigma Delta Number Power 0.0500 0.759484 0.049046 148 0.0813 ID[GENDER]

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99 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 4.6857143 0.24016992 F,NG 4.5909524 0.24016992 F,TYCHEM 4.7848589 0.25734609 F,TYV 4.2583333 0.24016992 F,WC 4.4932431 0.26326468 M,CC 3.6772478 0.17271745 M,NG 3.6709219 0.16920101 M,TYCHEM 3.6750176 0.17161575 M,TYV 3.9624494 0.17640330 M,WC 4.0042857 0.16982578

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100 Least Squares Fit Response MSA Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F ML 2 2 567744.40 558.0851 <.0001 GENDER 1 1 3379.99 6.6450 0.0107 Ensemble 4 4 819.21 0.4026 0.8066 GENDER*Ensemble 4 4 1869.79 0.9190 0.4539 ID[GENDER] 14 14 89177.15 12.5228 <.0001 GENDER*ML 2 2 207.55 0.2040 0.8156 ML Least Squares Means Table Level Least Sq Mean Std Error Mean M1 111.67242 3.4655702 114.732 M2 179.55324 3.8225026 180.043 M3 252.08461 3.7746999 253.812 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 173.94310 5.2588656 170.489 M 188.26374 1.7907827 188.875 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 177.98690 4.5545482 181.990 NG 183.68601 4.5059642 185.070 TY1427 181.49371 4.5203980 179.170 TYCHEM 179.25844 4.3804743 184.508 WC 183.09206 4.1402492 188.117 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 169.58810 8.1117875 F,NG 177.87204 8.1117875 F,TY1427 179.84698 8.1117875 F,TYCHEM 168.10401 7.7851015 F,WC 174.30439 7.2906034 M,CC 186.38570 4.1442179 M,NG 189.49998 3.9260357 M,TY1427 183.14043 3.9918538 M,TYCHEM 190.41287 4.0182602

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101 Level Least Sq Mean Std Error M,WC 191.87972 3.9260357 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error F,M1 102.97529 6.1761336 F,M2 173.46620 7.0007304 F,M3 245.38782 6.8937147 M,M1 120.36956 3.1458038 M,M2 185.64027 3.0717878 M,M3 258.78140 3.0773582 Response WBGT Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F ML 2 2 897.8666 165.7265 <.0001 GENDER 1 1 0.0836 0.0309 0.8607 Ensemble 4 4 1005.3415 92.7820 <.0001 GENDER*Ensemble 4 4 4.9040 0.4526 0.7704 ID[GENDER] 14 14 141.0609 3.7195 <.0001 GENDER*ML 2 2 14.0807 2.5990 0.0769 ML Least Squares Means Table Level Least Sq Mean Std Error Mean M1 35.446547 0.25290563 35.2049 M2 32.604100 0.27895335 32.4998 M3 29.856876 0.27546487 29.7806 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 32.671455 0.38377428 32.1835 M 32.600227 0.13068529 32.5630 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 34.243250 0.33237557 33.9767 NG 32.354446 0.32883007 32.2159 TY1427 34.033911 0.3298834134.1510 TYCHEM 28.180942 0.31967224 28.0487 WC 34.366657 0.30214143 34.1741

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102 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 34.348219 0.59197090 F,NG 32.482802 0.59197090 F,TY1427 33.734885 0.59197090 F,TYCHEM 28.272904 0.56813046 F,WC 34.518465 0.53204365 M,CC 34.138281 0.30243105 M,NG 32.226091 0.28650884 M,TY1427 34.332937 0.29131203 M,TYCHEM 28.088979 0.29323908 M,WC 34.214848 0.28650884 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error F,M1 35.733449 0.45071341 F,M2 32.783474 0.51088969 F,M3 29.497441 0.50308005 M,M1 35.159645 0.22957016 M,M2 32.424726 0.22416871 M,M3 30.216311 0.22457522 Response Tre Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F ML 2 2 4.7803507 35.7713 <.0001 GENDER 1 1 0.0137261 0.2054 0.6509 Ensemble 4 4 0.3870919 1.4483 0.2196 GENDER*Ensemble 4 4 0.4086949 1.5291 0.1953 ID[GENDER] 14 14 6.1620914 6.5873 <.0001 GENDER*ML 2 2 0.1055284 0.7897 0.4555 ML Least Squares Means Table Level Least Sq Mean Std Error Mean M1 37.530170 0.03972014 37.5126 M2 37.754806 0.04381107 37.7386 M3 37.937972 0.04326319 37.9485 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean

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103 Level Least Sq Mean Std Error Mean F 37.755412 0.06027374 37.7528 M 37.726553 0.02052480 37.7299 Ensemble Least Squares Means Table Level Least Sq Mean Std Error Mean CC 37.698084 0.05220131 37.6631 NG 37.719124 0.05164447 37.7398 TY1427 37.749219 0.05180990 37.7350 TYCHEM 37.826601 0.05020619 37.8180 WC 37.711886 0.04745288 37.7182 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 37.761127 0.09297211 F,NG 37.666127 0.09297211 F,TY1427 37.763627 0.09297211 F,TYCHEM 37.898165 0.08922784 F,WC 37.688015 0.08356022 M,CC 37.635041 0.04749837 M,NG 37.772121 0.04499770 M,TY1427 37.734811 0.04575207 M,TYCHEM 37.755036 0.04605472 M,WC 37.735758 0.04499770 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error F,M1 37.576222 0.07078688 F,M2 37.766541 0.08023788 F,M3 37.923474 0.07901134 M,M1 37.484119 0.03605519 M,M2 37.743071 0.03520686 M,M3 37.952470 0.03527071 Response HR Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F ML 2 2 13816.236 66.0475 <.0001 GENDER 1 1 2174.609 20.7911 <.0001 Ensemble 4 4 737.267 1.7622 0.1381

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104 Source Nparm DF Sum of Squares F Ratio Prob > F GENDER*Ensemble 4 4 525.989 1.2572 0.2883 ID[GENDER] 14 14 41460.047 28.3138 <.0001 GENDER*ML 2 2 530.193 2.5346 0.0819 ML Least Squares Means Table Level Least Sq Mean Std Error Mean M1 111.20834 1.5715024 110.333 M2 119.84081 1.7333574 116.986 M3 132.90026 1.7116807 130.613 GENDER Least Squares Means Table Level Least Sq Mean Std Error Mean F 127.05982 2.3846926 129.574 M 115.57312 0.8120509 115.581 Ensemble Least Squares Means Table Level Least Sq Mean Std ErrorMean CC 120.09367 2.0653118 117.143 NG 119.57750 2.0432808 118.800 TY1427 121.47674 2.0498260 119.000 TYCHEM 125.10962 1.9863760 124.174 WC 120.32481 1.8774432 117.795 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 127.41257 3.6783826 F,NG 122.24590 3.6783826 F,TY1427 127.82924 3.6783826 F,TYCHEM 132.34358 3.5302431 F,WC 125.46781 3.3060073 M,CC 112.77476 1.8792429 M,NG 116.90909 1.7803057 M,TY1427 115.12425 1.8101516 M,TYCHEM 117.87567 1.8221259 M,WC 115.18182 1.7803057 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error

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105 Level Least Sq Mean Std Error F,M1 114.60840 2.8006382 F,M2 126.01944 3.1745610 F,M3 140.55163 3.1260336 M,M1 107.80829 1.4265006 M,M2 113.66217 1.3929372 M,M3 125.24889 1.3954632 Response Tsk Whole Model Effect Tests Source Nparm DF Sum of Squares F Ratio Prob > F ML 2 2 45.137179 95.8702 <.0001 GENDER 1 1 0.030712 0.1305 0.7183 Ensemble 4 4 2.712920 2.8811 0.0239 GENDER*Ensemble 4 4 0.873114 0.9272 0.4492 ID[GENDER] 14 14 24.048220 7.2968 <.0001 GENDER*ML 2 2 3.797653 8.0661 0.0004 ML Least Squares Means Table Level Least Sq Mean Std Error Mean M1 36.693911 0.07455449 36.6491 M2 36.301233 0.0822331436.2744 M3 35.474111 0.0812047735.5953 GENDER Least Squares Means Table Level Least Sq Mean Std ErrorMean F 36.134835 0.1131334836.1541 M 36.178003 0.0385249436.1705 Ensemble Least Squares Means Table Level Least Sq Mean Std ErrorMean CC 36.053472 0.0979815736.0309 NG 36.121201 0.0969363936.1682 TY1427 36.030325 0.0972469036.0971 TYCHEM 36.363865 0.0942367436.3792 WC 36.213230 0.0890687936.1387 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 36.072099 0.17450813 F,NG 36.036432 0.17450813 F,TY1427 35.934182 0.17450813

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106 Level Least Sq Mean Std Error F,TYCHEM 36.316273 0.16748016 F,WC 36.315188 0.15684207 M,CC 36.034846 0.08915417 M,NG 36.205970 0.08446044 M,TY1427 36.126468 0.08587638 M,TYCHEM 36.411457 0.08644446 M,WC 36.111273 0.08446044 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error F,M1 36.825585 0.13286659 F,M2 36.325376 0.15060606 F,M3 35.253544 0.14830384 M,M1 36.562238 0.06767538 M,M2 36.277091 0.06608308 M,M3 35.694679 0.06620292 Response PSI Whole Model Effect Tests Source NparmDFSum of SquaresF Ratio Prob > F ML 2284.7751865.4493 <.0001 GENDER 115.836429.0118 0.0030 Ensemble 445.355962.0675 0.0866 GENDER*Ensemble 444.525111.7468 0.1413 ID[GENDER] 1414166.9494418.4129 <.0001 GENDER*ML 220.313930.2424 0.7850 ML Least Squares Means Table Level Least Sq Mean Std ErrorMean M1 3.4411575 0.123660343.37027 M2 4.2266200 0.136396604.06377 M3 5.1537750 0.134690875.06248 GENDER Least Squares Means Table Level Least Sq Mean Std ErrorMean F 4.5713928 0.187649674.68673 M 3.9763089 0.063899673.98234

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107 Ensemble Least Squares Means Table Level Least Sq Mean Std ErrorMean CC 4.1441244 0.162517843.94529 NG 4.1546116 0.160784244.15201 TY1427 4.2952099 0.161299284.15357 TYCHEM 4.5971735 0.156306444.53835 WC 4.1781349 0.147734604.06818 GENDER*Ensemble Least Squares Means Table Level Least Sq Mean Std Error F,CC 4.5977152 0.28944917 F,NG 4.1933502 0.28944917 F,TY1427 4.6217232 0.28944917 F,TYCHEM 5.0609217 0.27779219 F,WC 4.3832539 0.26014724 M,CC 3.6905335 0.14787621 M,NG 4.1158730 0.14009092 M,TY1427 3.9686967 0.14243948 M,TYCHEM 4.1334253 0.14338172 M,WC 3.9730159 0.14009092 ID[GENDER] GENDER*ML Least Squares Means Table Level Least Sq Mean Std Error F,M1 3.6798176 0.22038013 F,M2 4.5403984 0.24980383 F,M3 5.4939624 0.24598524 M,M1 3.2024973 0.11225027 M,M2 3.9128417 0.10960919 M,M3 4.8135876 0.10980795

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ABOUT THE AUTHOR Christina L. Luecke received a Master of Science in Public Health in Industrial Hygiene in 2000 from the University of S outh Florida (USF). She then managed a NIOSH Heat Stress Lab at USF for the next three years while she began work on her doctorate in Industrial Hygiene. She also worked as an OSHA Compliance Consultant, providing training and compliance services to medical and dent al professionals. She now works in Tampa, Florida doing comprehens ive industrial hygiene consulting for OHC Environmental Engineering.


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Luecke, Christina L.
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Gender differences during heat strain at ctitical WBGT
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by Christina L. Luecke.
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[Tampa, Fla] :
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2006.
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Dissertation (Ph.D.)--University of South Florida, 2006.
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Text (Electronic dissertation) in PDF format.
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ABSTRACT: Heat stress is influenced by environmental conditions, workload and clothing. A critical environment is the upper limit of compensable heat stress for a given metabolic rate and clothing ensemble. The physiological strains associated with heat stress are core and skin temperatures, heart rate and physiological strain index (psi). Because heat dissipation mechanisms may differ between men and women, there may be gender differences in the critical environment and the associated physiological variables. Gender differences were explored between acclimated men (n = 20) and women (n = 9) at the upper limit of compensable heat stress. Participants walked on a motorized treadmill at a target metabolic rate of 160W/m2 while wearing five different clothing ensembles (cotton work clothes, cotton coveralls, and three coveralls of particle barrier, liquid barrier, and vapor barrier properties). The starting air temperature (Tdb) was 34¨C and humidity was held constant at 50%. Once thermal equilibrium was achieved, Tdb was increased 1¨C every five minutes until loss of thermal equilibrium or termination criteria were met. Upon initial analysis, several gender differences were found. A significant difference (p = 0.035) was found for WBGTcrit, where values were 32.5¨C for men and 33.1¨C for women. Women had higher average heart rates (hr = 125 and 112 bpm), average skin temperatures (Tsk =36.4 and 36.2¨C), and psi values (4.5 and 3.8) than men. No significant difference was found between genders for core temperature (tre) (p = 0.147). The target metabolic rate of 160W/m2 was not achieved and there were significant differences (p < 0.0001) between men (172 W/m2) and women (152 W/m2). The effects of metabolic rate on WBGTcrit was examined and it was discovered that the difference in WGBTcrit could be explained by the difference in metabolic rate. The same logic was applied to the physiological responses and confirmed a difference betweengenders for Tre, HR, and PSI The differences for Tsk disappeared. These findings indicate that women experienced a greater cardiovascular strain at the critical conditon and also greater heat strain than men at the same heat load.
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Adviser: Candi D. Ashley, Ph.D.
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Heat stress.
Heat strain.
Heat balance.
Gender.
Physiological responses to heat.
Occupational heat exposure.
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