Core Temperature and Sweating in Men and Women During a 15-km Race in Cool Conditions

2020 ◽  
Vol 15 (8) ◽  
pp. 1132-1137
Author(s):  
Coen C.W.G. Bongers ◽  
Dominique S.M. ten Haaf ◽  
Nicholas Ravanelli ◽  
Thijs M.H. Eijsvogels ◽  
Maria T.E. Hopman
Keyword(s):  
Body Mass ◽  
Heat Production ◽  
Sweat Rate ◽  
Core Body Temperature ◽  
Whole Body ◽  
Ambient Conditions ◽  
External Work ◽  
Men And Women ◽  
The Impact ◽  
Cool Conditions

Purpose: Studies often assess the impact of sex on the relation between core body temperature (CBT), whole-body sweat rate (WBSR), and heat production during exercise in laboratory settings, but less is known in free-living conditions. Therefore, the authors compared the relation between CBT, WBSR, and heat production between sexes in a 15-km race under cool conditions. Methods: During 3 editions of the Seven Hills Run (Nijmegen, the Netherlands) with similar ambient conditions (8–12°C, 80–95% relative humidity), CBT and WBSR were measured among 375 participants (52% male) before and immediately after the 15-km race. Heat production was estimated using initial body mass and mean running speed, assuming negligible external work. Results: Men finished the race in 76 (12) minutes and women in 83 (13) minutes (P < .001, effect size [ES] = 0.55). Absolute heat production was higher in men than in women (1185 [163] W vs 867 [122] W, respectively, P < .001, ES = 1.47), even after normalizing to body mass (15.0 [2.2] W/kg vs 13.8 [1.9] W/kg, P < .001, ES = 0.56). Finish CBT did not differ between men and women (39.2°C [0.7°C] vs 39.2°C [0.7°C], P = .71, ES = 0.04). Men demonstrated a greater increase in CBT (1.5°C [0.8°C] vs 1.3°C [0.7°C], respectively, P = .013, ES = 0.31); the sex difference remains after correcting for heat production (P = .004). WBSR was larger in men (18.0 [6.9] g/min) than in women (11.4 [4.7] g/min; P < .001, ES = 0.97). A weak correlation between WBSR and heat production was found irrespective of sex (R2 = .395, P < .001). Conclusions: WBSR was associated with heat production, irrespective of sex, during a self-paced 15-km running race in cool environmental conditions. Men had a higher ΔCBT than women.

Impact of Age and Body Mass Index on Anthropometry in Working Adults

2017 ◽  
Vol 61 (1) ◽  
pp. 1341-1345 ◽  
Author(s):  
Zachary Merrill ◽  
April Chambers ◽  
Rakié Cham
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Center Of Mass ◽  
Biomechanical Model ◽  
Whole Body ◽  
Working Adults ◽  
Biomechanical Models ◽  
Scan Data ◽  
Body Segment Parameters ◽  
The Impact

Body segment parameters (BSPs) such as segment mass and center of mass are used as inputs in ergonomic design and biomechanical models to predict the risk of musculoskeletal injuries. These models have been shown to be sensitive to the BSP values used as inputs, demonstrating the necessity of using accurate and representative parameters. This study aims to provide accurate BSPs by quantifying the impact of age and body mass index on torso and thigh mass and center of mass in working adults using whole body dual energy x-ray absorptiometry (DXA) scan data. The results showed significant effects of gender, age, and body mass index (BMI) on torso and thigh mass and center of mass, as well as significant effects of age and BMI within genders, indicating that age, gender, and BMI need to be taken into account when predicting BSPs in order to calculate representative ergonomic and biomechanical model outputs.

scholarly journals Fluid Balance and Sodium Losses During Indoor Tennis Match Play

2011 ◽  
Vol 21 (6) ◽  
pp. 492-500 ◽  
Author(s):  
Matthew J.E. Lott ◽  
Stuart D.R. Galloway
Keyword(s):  
Heart Rate ◽  
Body Mass ◽  
Fluid Balance ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Fluid Replacement ◽  
Whole Body ◽  
Electrolyte Balance ◽  
Match Play ◽  
Tennis Match

This study assessed fluid balance, sodium losses, and effort intensity during indoor tennis match play (17 ± 2 °C, 42% ± 9% relative humidity) over a mean match duration of 68.1 ± 12.8 min in 16 male tennis players. Ad libitum fluid intake was recorded throughout the match. Sweat loss from change in nude body mass; sweat electrolyte content from patches applied to the forearm, calf, and thigh, and back of each player; and electrolyte balance derived from sweat, urine, and daily food-intake analysis were measured. Effort intensity was assessed from on-court heart rate compared with data obtained during a maximal treadmill test. Sweat rate (M ± SD) was 1.1 ± 0.4 L/hr, and fluid-ingestion rate was 1.0 ± 0.6 L/hr (replacing 93% ± 47% of fluid lost), resulting in only a small mean loss in body mass of 0.15% ± 0.74%. Large interindividual variabilities in sweat rate (range 0.3–2.0 L/hr) and fluid intake (range 0.31–2.52 L/hr) were noted. Whole-body sweat sodium concentration was 38 ± 12 mmol/L, and total sodium losses during match play were 1.1 ± 0.4 g (range 0.5–1.8 g). Daily sodium intake was 2.8 ± 1.1 g. Indoor match play largely consisted of low-intensity exercise below ventilatory threshold (mean match heart rate was 138 ± 24 beats/min). This study shows that in moderate indoor temperature conditions players ingest sufficient fluid to replace sweat losses. However, the wide range in data obtained highlights the need for individualized fluid-replacement guidance.

Responses to dry heat of men and women with similar aerobic capacities

1981 ◽  
Vol 50 (1) ◽  
pp. 65-70 ◽  
Author(s):  
A. J. Frye ◽  
E. Kamon
Keyword(s):  
Heat Stress ◽  
Menstrual Cycle ◽  
Strain State ◽  
Sweat Rate ◽  
Stress Tests ◽  
Ambient Conditions ◽  
Men And Women ◽  
Dry Heat ◽  
Before And After ◽  
Cardiovascular Strain

Four men and four women with similar VO2max (56.33 +/- 4.05 and 54.08 +/- 4.27 ml.kg-1.min-1, respectively) exercised up to 3 h at 30% VO2max during heat stress tests (HST) before and after acclimation to dry heat [dry-bulb temperature (Tdb)/wet-bulb temperature (Twb) = 48/25 degrees C]. Rectal (Tre), tympanic sweat on the chest (msw), and total sweat rate (Msw) were recorded. There were no differences in the responses of the women between phases of the menstrual cycle. Tre, Tty, Tsk, and Tdb at the onset of sweating were similar in both sexes before and after acclimation. The nonacclimated men had significantly higher Msw and slower rise in Tre as compared to the nonacclimated women. Following acclimation these differences were no longer evident. Acclimation produced an increase in Msw in both sexes that was characterized by an increase in sweating sensitivity (delta msw/delta Tre). It was concluded that sex alone does not determine responses to heat stress. Consideration should also be given to the relative cardiovascular strain, state of acclimation, and the ambient conditions.

Large differences in peak oxygen uptake do not independently alter changes in core temperature and sweating during exercise

2011 ◽  
Vol 301 (3) ◽  
pp. R832-R841 ◽  
Author(s):  
Ollie Jay ◽  
Anthony R. Bain ◽  
Tomasz M. Deren ◽  
Matthew Sacheli ◽  
Matthew N. Cramer
Keyword(s):  
Oxygen Uptake ◽  
Body Mass ◽  
Core Temperature ◽  
Heat Production ◽  
Exercise Intensity ◽  
Peak Oxygen Uptake ◽  
Whole Body ◽  
Complex Interactions ◽  
Relative Exercise Intensity ◽  
Sudomotor Activity

The independent influence of peak oxygen uptake (V̇o2 peak) on changes in thermoregulatory responses during exercise in a neutral climate has not been previously isolated because of complex interactions between V̇o2 peak, metabolic heat production (Hprod), body mass, and body surface area (BSA). It was hypothesized that V̇o2 peak does not independently alter changes in core temperature and sweating during exercise. Fourteen males, 7 high (HI) V̇o2 peak: 60.1 ± 4.5 ml·kg−1·min−1; 7 low (LO) V̇o2 peak: 40.3 ± 2.9 ml·kg−1·min−1 matched for body mass (HI: 78.2 ± 6.1 kg; LO: 78.7 ± 7.1 kg) and BSA (HI: 1.97 ± 0.08 m2; LO: 1.94 ± 0.08 m2), cycled for 60-min at 1) a fixed heat production (FHP trial) and 2) a relative exercise intensity of 60% V̇o2 peak (REL trial) at 24.8 ± 0.6°C, 26 ± 10% RH. In the FHP trial, Hprod was similar between the HI (542 ± 38 W, 7.0 ± 0.6 W/kg or 275 ± 25 W/m2) and LO (535 ± 39 W, 6.9 ± 0.9 W/kg or 277 ± 29 W/m2) groups, while changes in rectal (Tre: HI: 0.87 ± 0.15°C, LO: 0.87 ± 0.18°C, P = 1.00) and aural canal (Tau: HI: 0.70 ± 0.12°C, LO: 0.74 ± 0.21°C, P = 0.65) temperature, whole-body sweat loss (WBSL) (HI: 434 ± 80 ml, LO: 440 ± 41 ml; P = 0.86), and steady-state local sweating (LSRback) ( P = 0.40) were all similar despite relative exercise intensity being different (HI: 39.7 ± 4.2%, LO: 57.6 ± 8.0% V̇o2 peak; P = 0.001). At 60% V̇o2 peak, Hprod was greater in the HI (834 ± 77 W, 10.7 ± 1.3 W/kg or 423 ± 44 W/m2) compared with LO (600 ± 90 W, 7.7 ± 1.4 W/kg or 310 ± 50 W/m2) group (all P < 0.001), as were changes in Tre (HI: 1.43 ± 0.28°C, LO: 0.89 ± 0.19°C; P = 0.001) and Tau (HI: 1.11 ± 0.21°C, LO: 0.66 ± 0.14°C; P < 0.001), and WBSL between 0 and 15, 15 and 30, 30 and 45, and 45 and 60 min (all P < 0.01), and LSRback ( P = 0.02). The absolute esophageal temperature (Tes) onset for sudomotor activity was ∼0.3°C lower ( P < 0.05) in the HI group, but the change in Tes from preexercise values before sweating onset was similar between groups. Sudomotor thermosensitivity during exercise were similar in both FHP ( P = 0.22) and REL ( P = 0.77) trials. In conclusion, changes in core temperature and sweating during exercise in a neutral climate are determined by Hprod, mass, and BSA, not V̇o2 peak.

Fluid and Food Intake During Professional Men’s and Women’s Road-Cycling Tours

2007 ◽  
Vol 2 (1) ◽  
pp. 58-71 ◽  
Author(s):  
Tammie R. Ebert ◽  
David T. Martin ◽  
Brian Stephens ◽  
Warren McDonald ◽  
Robert T. Withers
Keyword(s):  
Body Mass ◽  
Cycling Performance ◽  
Men And Women ◽  
Nutritional Recommendations ◽  
Mass Losses ◽  
Road Cycling ◽  
Average Intake ◽  
Road Races ◽  
The Impact ◽  
Food Consumed

Purpose:To quantify the fluid and food consumed during a men’s and women’s professional road-cycling tour.Methods:Eight men (age 25 ± 5 y, body mass ± 7.4 kg, and height 177.4 ± 4.5 cm) and 6 women (age 26 ± 4 y, body mass ± 5.6 kg, and height 170.4 ± 5.2 cm) of the Australian Institute of Sport Road Cycling squads participated in the study. The men competed in the 6-d Tour Down Under (Adelaide, Australia), and the women, in the 10-d Tour De L’Aude (Aude, France). Body mass was recorded before and immediately after the race. Cyclists recalled the number of water bottles and amount of food they had consumed.Results:Men and women recorded body-mass losses of ~2 kg (2.8% body mass) and 1.5 kg (2.6% body mass), respectively, per stage during the long road races. Men had an average fluid intake of 1.0 L/h, whereas women only consumed on average 0.4 L/h. In addition, men consumed CHO at the rate suggested by dietitians (average CHO intake of 48 g/h), but again the women failed to reach recommendations, with an average intake of ~21 g/h during a road stage.Conclusions:Men appeared to drink and eat during racing in accordance with current nutritional recommendations, but women failed to reach these guidelines. Both men and women finished their races with a body-mass loss of ~2.6% to 2.8%. Further research is required to determine the impact of this loss on road-cycling performance and thermoregulation.

scholarly journals Individual characteristics associated with the magnitude of heat acclimation adaptations

2021 ◽  
Author(s):  
Puck Alkemade ◽  
Nicola Gerrett ◽  
Thijs M. H. Eijsvogels ◽  
Hein A. M. Daanen
Keyword(s):  
Body Mass ◽  
Sweat Rate ◽  
Heat Acclimation ◽  
Individual Characteristics ◽  
Whole Body ◽  
Stress Tests ◽  
Adaptive Responses ◽  
Body Dimensions ◽  
Low Responders ◽  
High Responders

Abstract Purpose The magnitude of heat acclimation (HA) adaptations varies largely among individuals, but it remains unclear what factors influence this variability. This study compared individual characteristics related to fitness status and body dimensions of low-, medium-, and high responders to HA. Methods Twenty-four participants (9 female, 15 male; maximum oxygen uptake [$$\dot{{V}}$$ V ˙ O2peak,kg] 52 ± 9 mL kg−1 min−1) completed 10 daily controlled-hyperthermia HA sessions. Adaptations were evaluated by heat stress tests (HST; 35 min cycling 1.5 W  kg−1; 33 °C, 65% relative humidity) pre- and post-HA. Low-, medium-, and high responder groups were determined based on tertiles (n = 8) of individual adaptations for resting rectal temperature (Tre), exercise-induced Tre rise (ΔTre), whole-body sweat rate (WBSR), and heart rate (HR). Results Body dimensions (p > 0.3) and $$\dot{{V}}$$ V ˙ O2peak,kg (p > 0.052) did not differentiate low-, medium-, and high responders for resting Tre or ΔTre. High WBSR responders had a larger body mass and lower body surface area-to-mass ratio than low responders (83.0 ± 9.3 vs 67.5 ± 7.3 kg; 249 ± 12 vs 274 ± 15 cm2 kg−1, respectively; p < 0.005). Conversely, high HR responders had a smaller body mass than low responders (69.2 ± 6.8 vs 83.4 ± 9.4 kg; p = 0.02). $$\dot{{V}}$$ V ˙ O2peak,kg did not differ among levels of responsiveness for WBSR and HR (p > 0.3). Conclusion Individual body dimensions influenced the magnitude of sudomotor and cardiovascular adaptive responses, but did not differentiate Tre adaptations to HA. The influence of $$\dot{{V}}$$ V ˙ O2peak,kg on the magnitude of adaptations was limited.

scholarly journals Effect of Pre-Exercise Caffeine Intake on Endurance Performance and Core Temperature Regulation During Exercise in the Heat: A Systematic Review with Meta-Analysis

2021 ◽  
Author(s):  
Catherine Naulleau ◽  
David Jeker ◽  
Timothee Pancrate ◽  
Pascale Claveau ◽  
Thomas A Deshayes ◽  
...  
Keyword(s):  
Systematic Review ◽  
Body Mass ◽  
Core Temperature ◽  
Meta Analysis ◽  
Endurance Performance ◽  
Rate Of Change ◽  
Caffeine Intake ◽  
Ambient Conditions ◽  
Physiological Strain ◽  
The Impact

Background: Heat is associated with physiological strain and endurance performance (EP) impairments. Studies have investigated the impact of caffeine intake upon EP and core temperature (CT) in the heat, but results are conflicting. There is a need to systematically determine the impact of pre-exercise caffeine intake in the heat. Objective: Use a meta-analytical approach to determine the effect of pre-exercise caffeine intake on EP and CT in the heat. Design: Systematic review with meta-analysis. Data sources: Four databases and cross-referencing. Data analysis: Weighted mean effect summaries using random-effects models for EP and CT, as well as meta regressions with robust standard errors to explore confounders. Study selection: Placebo-controlled, randomized studies in adults (≥ 18 yrs old) with caffeine intake at least 30 min before endurance exercise ≥ 30 min, performed in ambient conditions ≥ 27°C. Results: Respectively 6 and 12 studies examined caffeine's impact on EP and CT, representing 52 and 205 endurance-trained individuals. On average, 6 mg/kg body mass of caffeine were taken 1 h before exercises of 70 min conducted at 34°C and 47% relative humidity. Caffeine supplementation improved EP by 2.0 +/- 0.7% (95% CI: 0.6 to 3.5%) and increased the rate of change in CT by 0.10 +/- 0.04°C/h (95% CI: 0.03 to 0.16°C/h), compared with the ingestion of a placebo. Conclusion: Caffeine ingestion of 6 mg/kg body mass 1 h before an exercise in the heat provides a worthwhile improvement in EP of 2%, while trivially increasing the rate of change in CT by 0.10°C/h.

scholarly journals Body mapping of regional sweat distribution in young and older males

2020 ◽  
Author(s):  
Nicole A. Coull ◽  
Anna M. West ◽  
Simon G. Hodder ◽  
Patrick Wheeler ◽  
George Havenith
Keyword(s):  
Heat Production ◽  
Thermal Sensation ◽  
Sweat Rate ◽  
Whole Body ◽  
Body Region ◽  
Sweat Loss ◽  
Body Mapping ◽  
Body Regions ◽  
Age Related ◽  
Older Males

Abstract Purpose Given the pressing impact of global warming and its detrimental effect on the health of older populations, understanding age-related changes in thermoregulatory function is essential. Age differences in regional sweat distribution have been observed previously, but given the typically small measurement areas assessed, the development of whole body sweat maps for older individuals is required. Therefore, this study investigated age-related differences in regional sweat distribution in a hot environment (32 °C/50%RH) in young and older adults, using a body mapping approach. Methods Technical absorbent pads were applied to the skin of 14 young (age 24 ± 2 years) and 14 older (68 ± 5 years) males to measure regional sweat rate (RSR) at rest (30 min) and during exercise (30 min), at a fixed heat production (200 W m−2). Gastrointestinal (Tgi) and skin temperature (Tsk), heart rate, thermal sensation, and thermal comfort were also measured. Results Whole body sweat maps showed that despite equal heat production, healthy older males had significantly lower gross sweat loss (GSL) than the young and significantly lower RSR at almost all body regions at rest and at the hands, legs, ankles, and feet during exercise. The lower sweat loss in the older group coincided with a greater increase in Tgi and a consistently higher Tsk at the legs, despite subjectively feeling slightly cooler than younger individuals. Conclusion These findings support the evidence of age-related deterioration in both autonomic and subjective responses in the heat and highlight the lower extremities as the most affected body region.

scholarly journals A comparison of thermoregulatory responses to exercise between mass-matched groups with large differences in body fat

2016 ◽  
Vol 120 (6) ◽  
pp. 615-623 ◽  
Author(s):  
Sheila Dervis ◽  
Geoff B. Coombs ◽  
Georgia K. Chaseling ◽  
Davide Filingeri ◽  
Jovana Smoljanic ◽  
...  
Keyword(s):  
Lean Body Mass ◽  
Body Mass ◽  
Body Fat ◽  
Sweat Rate ◽  
Whole Body ◽  
Total Body Mass ◽  
Percentage Body Fat ◽  
Thermoregulatory Responses ◽  
Local Sweat Rate ◽  
Total Body

We sought to determine 1) the influence of adiposity on thermoregulatory responses independently of the confounding biophysical factors of body mass and metabolic heat production (Hprod); and 2) whether differences in adiposity should be accounted for by prescribing an exercise intensity eliciting a fixed Hprod per kilogram of lean body mass (LBM). Nine low (LO-BF) and nine high (HI-BF) body fat males matched in pairs for total body mass (TBM; LO-BF: 88.7 ± 8.4 kg, HI-BF: 90.1 ± 7.9 kg; P = 0.72), but with distinctly different percentage body fat (%BF; LO-BF: 10.8 ± 3.6%; HI-BF: 32.0 ± 5.6%; P < 0.001), cycled for 60 min at 28.1 ± 0.2°C, 26 ± 8% relative humidity (RH), at a target Hprod of 1) 550 W (FHP trial) and 2) 7.5 W/kg LBM (LBM trial). Changes in rectal temperature (ΔTre) and local sweat rate (LSR) were measured continuously while whole body sweat loss (WBSL) and net heat loss (Hloss) were estimated over 60 min. In the FHP trial, ΔTre (LO-BF: 0.66 ± 0.21°C, HI-BF: 0.87 ± 0.18°C; P = 0.02) was greater in HI-BF, whereas mean LSR (LO-BF 0.52 ± 0.19, HI-BF 0.43 ± 0.15 mg·cm−2·min−1; P = 0.19), WBSL (LO-BF 586 ± 82 ml, HI-BF 559 ± 75 ml; P = 0.47) and Hloss (LO-BF 1,867 ± 208 kJ, HI-BF 1,826 ± 224 kJ; P = 0.69) were all similar. In the LBM trial, ΔTre (LO-BF 0.82 ± 0.18°C, HI-BF 0.54 ± 0.19°C; P < 0.001), mean LSR (LO-BF 0.59 ± 0.20, HI-BF 0.38 ± 0.12 mg·cm−2·min−1; P = 0.04), WBSL (LO-BF 580 ± 106 ml, HI-BF 381 ± 68 ml; P < 0.001), and Hloss (LO-BF 1,884 ± 277 kJ, HI-BF 1,341 ± 184 kJ; P < 0.001) were all greater at end-exercise in LO-BF. In conclusion, high %BF individuals demonstrate a greater ΔTre independently of differences in mass and Hprod, possibly due to a lower mean specific heat capacity or impaired sudomotor control. However, thermoregulatory responses of groups with different adiposity levels should not be compared using a fixed Hprod in watts per kilogram lean body mass.

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