Authors: Nicholas M Ravanelli Matthew N Cramer Yannick MolgatSeon Anthony N Carlsen Ollie Jay
Publish Date: 2014/08/05
Volume: 114, Issue: 11, Pages: 2399-2410
Abstract
Eight trained volunteers cycled in 19 °C/18 kPa COOL 25 °C/12 kPa NORM and 34 °C/16 kPa HOT while maintaining an RPE of 16 Potential differences in S following the onset of exercise were assessed by comparing rates of esophageal temperature change ΔT es/Δt and estimated S values using a traditional twocompartment thermometric model S therm of changes in rectal T re and skin T sk temperature and partitional calorimetry S calAfter 15 min of exercise workload decreased more in HOT vs COOL P = 003 resulting in a shorter time HOT 407 ± 149 min COOL 535 ± 187 min P = 004 to 70 of initial workload However there were no preceding differences in ΔT es/Δt between conditions P = 018 S therm values were different between HOT and COOL during the first 5 min of exercise P 005 primarily due to negative S therm values −32 ± 15 kJ min−1 in COOL which according to partitional calorimetric measurements required improbably high ~56 kJ min−1 rates of evaporation when no sweating on the back and thigh was observed until after 76 ± 15 min and 48 ± 17 min of exercise respectively S cal values in the first 5 min of exercise confirmed S was actually positive in COOL +21 ± 8 kJ min−1 and not negative Different S therm values following the onset of exercise at different environmental temperatures are simply due to transient differences in the rate of change in T sk
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