Limbaugh JD, Wimer GS, Long LH, Baird WH. Body fatness, body core temperature, and heat loss during moderate-intensity exercise. Aviat Space Environ Med 2013; 84:1153–8.
Purpose:
This study examined the influence of body fatness on body core temperature
and heat loss responses during moderate-intensity exercise.
Methods:
Nine men with lower body fat and eight men with higher body fat, matched for aerobic fitness, completed 1 h of recumbent cycling at the same absolute intensity in a warm environment (30°C, 40% RH). Percent
body fat was measured by hydrostatic weighing, using oxygen dilution to determine residual volume. Esophageal temperature (Tes), mean skin temperature (<inline-graphic xlink:href="1153inf1.gif"/>), and local sweat rate (<inline-graphic xlink:href="1153inf2.gif"/>sw)
were measured at rest and continuously during exercise while forearm blood flow (FBF) was measured at rest and every 10 min during exercise.
Results:
The lower body fat and higher body fat groups were successfully matched for aerobic fitness, removing the influence of body fatness,
given that <inline-graphic xlink:href="1153inf3.gif"/>o2peak was 50.72 ± 7.34 and 50.43 ± 5.01 ml · kg LBM−1
· min−1, respectively. When compared to lower body fat individuals, % body fat, body surface
area (AD), and body mass were higher and AD/mass was lower in higher body fat individuals. Tes, <inline-graphic xlink:href="1153inf1.gif"/>, FBF, <inline-graphic xlink:href="1153inf2.gif"/>sw, and the slope of <inline-graphic xlink:href="1153inf2.gif"/>sw:Tes
were not different between groups. Metabolic heat production was similar between the lower body fat (299.7 ± 40.5 W · m−2) and higher body fat (288.1 ± 30.6 W · m−2) subjects, respectively. Dry and evaporative heat
loss, as well as heat storage during exercise, were not different between groups.
Conclusion:
These data suggest that there is no effect of body fatness on body core temperature or heat loss responses during moderate-intensity exercise in a warm environment.