Differences in dry-bulb temperature do not influence moderate-duration exercise performance in warm environments when vapor pressure is equivalent

Lei, Tze‐Huan; Schlader, Zachary J.; Muhamed, Ahmad Munir Che; Zheng, Huixin; Stannard, Stephen R.; Kondo, Narihiko; Cotter, James D.; Mündel, Toby

doi:10.1007/s00421-020-04322-8

Cited by 13 publications

(11 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notably, this decrement in performance from a moderate to heat-stressful environment (3% : 5 W) is significantly lower (P = 0.01, independent t test) than the effect a more humid environment confers when compared with dry heat (7% : 8 W) in a similar cohort of trained females, i.e., 4.5 ± 0.8 W•kg À1 versus 4.2 ± 0.4 W•kg À1 (26), on account of a reduced evaporative power of the body to the environment (43,44). Therefore, the current results support our previous studies, which have all utilized a 30-min work trial, in demonstrating that it is the (absolute) humidity of a heat-stressful environment that imposes a greater influence on performance than ambient temperature per se (25,26,45).…”

Section: Discussionsupporting

confidence: 87%

Menstrual phase and ambient temperature do not influence iron regulation in the acute exercise period

Zheng

Badenhorst

Lei

et al. 2021

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

View full text Add to dashboard Cite

The current study investigated whether ambient heat augments the inflammatory and post-exercise hepcidin response in women, and if menstrual phase and/or self-pacing modulate these physiological effects. Eight trained females (age: 37±7 y; VO2max: 46±7 mL∙kg-1∙min-1; peak power output: 4.5±0.8 W∙kg-1) underwent 20 min of fixed-intensity cycling (100 and 125 W) followed by a 30-min work trial (≈75% VO2max) in a moderate (MOD: 20±1 °C, 53±8% relative humidity) and warm-humid (WARM: 32±0 °C, 75±3% relative humidity) environment in both their early follicular (days 5±2) and mid-luteal (days 21±3) phases. Mean power output was 5±4 W higher in MOD than in WARM (p=0.02) such that the difference in core temperature rise was limited between environments (-0.29±0.18 °C in MOD, p<0.01). IL-6 and hepcidin both increased post-exercise (198% and 38%, respectively), however, neither were affected by ambient temperature or menstrual phase (all p>0.15). Multiple regression analysis demonstrated that the IL-6 response to exercise was explained by leukocyte and platelet count (r2=0.72, p<0.01) and the hepcidin response to exercise was explained by serum iron and ferritin (r2=0.62, p<0.01). During exercise participants almost matched their fluid loss (0.48±0.18 kg·h-1) with water intake (0.35±0.15 L·h-1) such that changes in body mass (-0.3±0.3%) and serum osmolality (0.5±2.0 mOsm·kg-1) were minimal or negligible, indicating a behavioral fluid-regulatory response. These results indicate that trained, iron sufficient women suffer no detriment to their iron regulation in response to exercise with acute ambient heat stress or between menstrual phases on account of a performance-physiological trade-off.

show abstract

Section: Discussionsupporting

confidence: 87%

Menstrual phase and ambient temperature do not influence iron regulation in the acute exercise period

Zheng

Badenhorst

Lei

et al. 2021

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

View full text Add to dashboard Cite

show abstract

“…Limitations of the present study include the relatively small number of combinations of E req , H prod , core temperatures and skin temperatures assessed. However, recent evidence supports present findings during self-paced exercise at higher rates of H prod and different ambient temperatures yet similar E req (Lei et al 2020). Further work is warranted to confirm present findings under conditions with greater H prod and/or more challenging environments for evaporative heat loss (i.e.…”

Section: Perspectivessupporting

confidence: 84%

Steady‐state sweating during exercise is determined by the evaporative requirement for heat balance independently of absolute core and skin temperatures

Ravanelli

Imbeault

Jay

2020

The Journal of Physiology

View full text Add to dashboard Cite

When exercise was prescribed to elicit a fixed evaporative heat balance requirement (E req ), no differences in steady-state sweat rates were observed with different absolute oesophageal and/or skin temperatures, secondary to differences in time of the day (i.e. morning (AM) vs. afternoon (PM)) and ambient temperature (i.e. 23°C vs. 33°C).r Exercise at a fixed metabolic heat production (H prod ), but a different E req (due to differences in air temperature), yielded higher steady-state sweat rates with a higher E req , irrespective of absolute oesophageal temperature.r Circadian rhythm did not alter the change in core temperature prior to the onset for sudomotor activation, nor the thermosensitivity, resulting in similar cumulative whole-body sweat rates irrespective of time of day at a fixed E req .r Collectively, these data indicate that during exercise in a compensable environment, steady-state sudomotor responses are influenced by E req rather than absolute core and skin temperatures, or H prod .

show abstract

“…All authors independently evaluated each sport, and the average overall categorization is presented in Table 1. For simplicity this presented as grouping of sports into 3-sub groups (based on the summarized score of predictability, decisionmaking and movement-difficulty) with low representing a score below 6, moderate [for scores [7][8][9] and high complexity [10][11][12]) as this grouping was considered relevant for the MCIL risk assessmenti.e. if tasks are likely to have low, moderate or high vulnerability to heat stress impacts on motorcognitive performance for a given MCIL (see Appendix 1 for overview of individual sport scores).…”

Section: Movement Skills and Their Difficultymentioning

confidence: 99%

“…With climate changes and a rise in the mean global temperature expected to continue toward the end of the 21 st century [5,6], future Summer Olympics and other major sport events are likely facing frequent and escalating environmental heat-load scenarios. All sports ranging from endurance to strength-and cognitively-dominated disciplines are susceptible to the detrimental effects of heat stress related to elevated environmental air temperature [7,8], high humidity [9,10], and solar radiation [11][12][13]; although via quite different mechanisms. These may include hyperthermia-induced impacts on the central nervous systems (CNS fatigue or function) or peripheral (cardiovascular and muscular) effects and operate both independently as well as in interaction [7,8,[14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Proposed framework for forecasting heat-effects on motor-cognitive performance in the Summer Olympics

et al. 2021

View full text Add to dashboard Cite

Heat strain impairs performance across a broad spectrum of sport disciplines. The impeding effects of hyperthermia and dehydration are often ascribed to compromised cardiovascular and muscular functioning, but expert performance also depends on appropriately tuned sensory, motor and cognitive processes. Considering that hyperthermia has implications for central nervous system (CNS) function and fatigue, it is highly relevant to analyze how heat stress forecasted for the upcoming Olympics may influence athletes. This paper proposes and demonstrates the use of a framework combining expected weather conditions with a heat strain and motor-cognitive model to analyze the impact of heat and associated factors on discipline- and scenario-specific performances during the Tokyo 2021 games. We pinpoint that hyperthermia-induced central fatigue may affect prolonged performances and analyze how hyperthermia may impair complex motor-cognitive performance, especially when accompanied by either moderate dehydration or exposure to severe solar radiation. Interestingly, several short explosive performances may benefit from faster cross-bridge contraction velocities at higher muscle temperatures in sport disciplines with little or no negative heat-effect on CNS fatigue or motor-cognitive performance. In the analyses of scenarios and Olympic sport disciplines, we consider thermal impacts on “motor-cognitive factors” such as decision-making, maximal and fine motor-activation as well as the influence on central fatigue and pacing. From this platform, we also provide perspectives on how athletes and coaches can identify risks for their event and potentially mitigate negative motor-cognitive effects for and optimize performance in the environmental settings projected.

show abstract

Differences in dry-bulb temperature do not influence moderate-duration exercise performance in warm environments when vapor pressure is equivalent

Cited by 13 publications

References 44 publications

Menstrual phase and ambient temperature do not influence iron regulation in the acute exercise period

Menstrual phase and ambient temperature do not influence iron regulation in the acute exercise period

Steady‐state sweating during exercise is determined by the evaporative requirement for heat balance independently of absolute core and skin temperatures

Proposed framework for forecasting heat-effects on motor-cognitive performance in the Summer Olympics

Contact Info

Product

Resources

About