Magalhães Flávio de Castro, Machado-Moreira Christiano Antônio, Vimieiro-Gomes Ana Carolina, Silami-Garcia Emerson, Lima Nilo Resende Viana, Rodrigues Luiz Oswaldo Carneiro
Laboratório de Fisiologia do Exercicio, Escola de Educação Física Fisioterapia e Terapia Ocupacional, Universidade Federal de Minas Gerais, Brazil.
J Physiol Anthropol. 2006 May;25(3):215-9. doi: 10.2114/jpa2.25.215.
The aim of the present study was to evaluate the sweat loss response during short-term heat acclimation in tropical natives. Six healthy young male subjects, inhabitants of a tropical region, were heat acclimated by means of nine days of one-hour heat-exercise treatments (40+/-0 degrees C and 32+/-1% relative humidity; 50% (.)VO(2peak) on a cycle ergometer). On days 1 to 9 of heat acclimation whole-body sweat loss was calculated by body weight variation corrected for body surface area. On days 1 and 9 rectal temperature (T(re)) and heart rate (HR) were measured continuously, and rating of perceived exertion (RPE) every 4 minutes. Heat acclimation was confirmed by reduced HR (day 1 rest: 77+/-5 b.min(-1); day 9 rest: 68+/-3 b.min(-1); day 1 final exercise: 161+/-15 b.min(-1); day 9 final exercise: 145+/-11 b.min(-1), p<0.05), RPE (13 vs. 11, p<0.05) and T(re) (day 1 rest: 37.2+/-0.2 degrees C; day 9 rest: 37.0+/-0.2 degrees C; day 1 final exercise: 38.2+/-0.2 degrees C; day 9 final exercise: 37.9+/-0.1 degrees C, p<0.05). The main finding was that whole-body sweat loss increased in days 5 and 7 (9.49+/-1.84 and 9.56+/-1.86 g.m(-2).min(-1), respectively) compared to day 1 (8.31+/-1.31 g.m(-2).min(-1), p<0.05) and was not different in day 9 (8.48+/-1.02 g.m(-2).min(-1)) compared to day 1 (p>0.05) of the protocol. These findings are consistent with the heat acclimation induced adaptations and suggest a biphasic sweat response (an increase in the sweat rate in the middle of the protocol followed by return to initial values by the end of it) during short-term heat acclimation in tropical natives.
本研究的目的是评估热带地区原住民在短期热适应过程中的出汗量反应。六名健康的年轻男性受试者，均为热带地区居民，通过为期九天、每天一小时的热锻炼处理（40±0℃，相对湿度32±1%；在自行车测力计上以50%的最大摄氧量运动）进行热适应。在热适应的第1至9天，通过根据体表面积校正的体重变化来计算全身出汗量。在第1天和第9天，连续测量直肠温度（T(re)）和心率（HR），并每4分钟测量一次主观用力程度（RPE）。热适应通过心率降低得到证实（第1天休息时：77±5次/分钟；第9天休息时：68±3次/分钟；第1天最后锻炼时：161±15次/分钟；第9天最后锻炼时：145±11次/分钟，p<0.05）、主观用力程度降低（13对11，p<0.05）以及直肠温度降低（第1天休息时：37.2±0.2℃；第9天休息时：37.0±0.2℃；第1天最后锻炼时：38.2±0.2℃；第9天最后锻炼时：37.9±0.1℃，p<0.05）。主要发现是，与第1天（8.31±1.31克·平方米·分钟(-1)）相比，全身出汗量在第5天和第7天增加（分别为9.49±1.84和9.56±1.86克·平方米·分钟(-1)，p<0.05），而与方案第1天相比，第9天（8.48±1.02克·平方米·分钟(-1)）无差异（p>0.05）。这些发现与热适应引起的适应性变化一致，并表明热带地区原住民在短期热适应过程中存在双相出汗反应（在方案中期出汗率增加，随后在方案结束时恢复到初始值）。
