Effects of heat acclimatisation on work tolerance and thermoregulation in trained tropical natives

摘要

This study aimed to investigate the effects of heat acclimatisation on thermoregulatory responses and work tolerance in trained individuals residing in the tropics. Eighteen male trained soldiers, who are native to a warm and humid climate, performed a total of four heat stress tests donning the Skeletal Battle Order (SBO, 20.5 kg) and Full Battle Order (FBO, 24.7 kg) before (PRE) and after (POST) a 10-day heat acclimatisation programme. The trials were conducted in an environmental chamber (dry bulb temperature: 32 degrees C, relative humidity: 70%, solar radiation: 400 W/m(2)). Excluding the data sets of which participants fully completed the heat stress tests (210 min) before and after heat acclimatisation, work tolerance was improved from 173 +/- 30 to 201 +/- 18 min (similar to 21%, p < 0.05, n=9) following heat acclimatisation. Following heat acclimatisation, chest skin temperature during exercise was lowered in SBO (PRE=36.7 +/- 0.3 vs. POST=36.5 +/- 0.3 degrees C, p < 0.01) and FBO (PRE=36.8 +/- 0.4 vs. POST=36.6 +/- 0.3 degrees C, p < 0.01). Ratings of perceived exertion were decreased with SBO and FBO (PRE=11 +/- 2: POST=10 +/- 2; p < 0.05) after heat acclimatisation. Heat acclimatisation had no effects on baseline body core temperature, heart rate and sweat rate across trials (p > 0.05). A heat acclimatisation programme improves work tolerance with minimal effects on thermoregulation in trained tropical natives