Possible biphasic sweating response during short-term heat acclimation protocol for tropical natives

Area of Science:

• Environmental Physiology
• Human Adaptation to Heat

Background:

• Short-term heat acclimation is crucial for individuals living in hot climates.
• Understanding sweat loss response is key to assessing thermoregulatory adaptation.

Purpose of the Study:

• To evaluate the sweat loss response during short-term heat acclimation in tropical natives.
• To investigate the physiological adaptations to heat exposure in this population.

Main Methods:

• Nine days of daily one-hour heat-exercise treatments (40°C, 32% RH, 50% VO2peak) were administered to six tropical male subjects.
• Whole-body sweat loss was measured by body weight variation corrected for body surface area.
• Rectal temperature (Tre), heart rate (HR), and rating of perceived exertion (RPE) were monitored.

Main Results:

• Heat acclimation was confirmed by significant reductions in HR and RPE, and a decrease in Tre.
• Whole-body sweat loss increased on days 5 and 7 compared to day 1 (p<0.05).
• Sweat loss on day 9 was not significantly different from day 1, suggesting a biphasic response.

Conclusions:

• Tropical natives exhibit a biphasic sweat loss response during short-term heat acclimation.
• This pattern of sweat response is consistent with heat acclimation-induced physiological adaptations.
• The findings highlight the dynamic nature of thermoregulation during heat exposure in tropical populations.