The effects of short-term aerobic training program in a hot \nAnd cold environment on thermoregulation, sweat \nSecretion and composition
Year: 2005
Type: article
Abstract: The effect of low-intensity exercise 1n the heat on thermoregulation and some \nbiochem~cal changes in temperate and tropical subjects under poorly and well-hydrated states \nwas examined. Two V02m£L-c matched groups of subjects consisting of 8 Japanese (JS) and 8 \nMalaysians (MS) participated in this study under two conditions. They are poorly-hydrated (no \nwater was given) and well-hydrated (3 rnl. Kg-1 body weight of water was provided at onset of \nexercise, 15th, 35th and 55th min of exercise). Experimental room in both countries was adjusted \nto a constant level (Ta: 31.5±0.03°C, rh: 72.9±0.1 %). Subjects spent an initial 10 min rest, 60 \nmin of cycling at 40% V02max and then 40 min recovery in the experimental room. Rectal \ntemperatures (Tre) skin temperatures (Tsk), heart rate (HR), heat-activated sweat glands density \n(HASG), local sweat rate (Msw-back) and percent dehydration were recorded during the test. \nBlood samples were analysed for plasma glucose and lactate levels. \nThe extent of dehydration was significantly higher in the combined groups of JS ( 1.43± \n0.08%) con1pared to MS (1.15±0.05%). During exercise Msw-back was significantly higher in JS \ncompared to MS in the well-hydrated condition. The HASG was significantly more in JS \ncompared toMS at rest and recovery. Tre was higher in MS during the test. Tsk was significantly \nhigher starting at the 5th of exercise until the end of the recovery period in MS compared to JS. \nIn conclusion, tropical natives have lower Msw-back as a result of higher Tsk and Tre during \ntest. However, temperate natives have higher Msw-bock and thus both Tsk and Tre, were lower \nduring experiments in the hot environment. This phenon1enon occurs in both poorly-hydrated \nand well-hydrated states at low intensity of exercise in hot environ1nent. The difference in Msw-bnck Tsk and Tre, is probably due to vasodilation which occurred during passive heat exposure \nin tropical natives.
Author: Sirisinghe, Roland Gamini
Language: English
Subfield: Physiology (medical)
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W7028151219