Whole-body pre-cooling and heat storage during self-paced cycling performance in warm humid conditions.
The aim of this study was to establish the effect that pre-cooling the skin without a concomitant reduction in core temperature has on subsequent self-paced cycling performance under warm humid (31 degrees C and 60% relative humidity) conditions. Seven moderately trained males performed a 30 min self-paced cycling trial on two separate occasions. The conditions were counterbalanced as control or whole-body pre-cooling by water immersion so that resting skin temperature was reduced by approximately 5-6 degrees C. After pre-cooling, mean skin temperature was lower throughout exercise and rectal temperature was lower (P < 0.05) between 15 and 25 min of exercise. Consequently, heat storage increased (P < 0.003) from 84.0+/-8.8 W x m(-2) to 153+/-13.1 W x m(-2) (mean +/- s(mean)) after pre-cooling, while total body sweat fell from 1.7+/-0.1 l x h(-1) to 1.2+/-0.1 l h(-1) (P < 0.05). The distance cycled increased from 14.9+/-0.8 to 15.8+/-0.7 km (P < 0.05) after pre-cooling. The results indicate that skin pre-cooling in the absence of a reduced rectal temperature is effective in reducing thermal strain and increasing the distance cycled in 30 min under warm humid conditions.
Kay
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Human Movement Studies Unit, Charles Sturt University, Bathurst, NSW, Australia.
Taaffe
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DR
Marino
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FE
D000293:Adolescent; D000328:Adult; D001642:Bicycling; D001833:Body Temperature Regulation / Q000502:physiology*; D003080:Cold Temperature; D004781:Environmental Exposure; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D007101:Immersion; D007773:Lactates / Q000097:blood; D008297:Male; D012143:Respiratory Physiological Phenomena; D012881:Skin Temperature; D013546:Sweating
D007773:Lactates