Research Institute for Sport and Exercise, University of Canberra, Canberra, Australia.
Thermal Ergonomics Laboratory, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.
J Appl Physiol (1985). 2021 Sep 1;131(3):1176-1185. doi: 10.1152/japplphysiol.01059.2020. Epub 2021 Jul 29.
The effects of dry-bulb temperature on self-paced exercise performance, along with thermal, cardiovascular, and perceptual responses, were investigated by minimizing differences in the skin-to-air vapor pressure gradient ( - ) between four temperatures. Fourteen trained male cyclists performed 30-km time trials in 13°C and 44% relative humidity (RH), 20°C and 70% RH, 28°C and 78% RH, and 36°C and 72% RH. Power output was similar in 13°C (275 ± 31 W; means and SD) and 20°C (272 ± 28 W; = 1.00), lower in 36°C (228 ± 36 W) than 13°C, 20°C, and 28°C (262 ± 27 W; < 0.001) and lower in 28°C than at 13°C and 20°C ( < 0.001). Peak rectal temperature was higher in 36°C (39.6 ± 0.4°C) than in all conditions ( < 0.001) and higher in 28°C (39.1 ± 0.4°C) than 13°C (38.7 ± 0.3°C; < 0.001) and 20°C (38.8 ± 0.3°C; < 0.01). Mean heart rate was higher in 36°C (163 ± 14 beats·min) than all conditions ( < 0.001) and higher in 20°C (156 ± 11 beats·min; = 0.009) and 28°C (159 ± 11 beats·min; < 0.001) than 13°C (153 ± 11 beats·min). Mean cardiac output was lower in 36°C (16.8 ± 2.5 L·min) than all conditions ( < 0.001) and lower in 28°C (18.6 ± 1.6 L·min) than 20°C (19.4 ± 2.0 L·min; = 0.004). Ratings of perceived exertion were higher in 36°C than all conditions ( < 0.001) and higher in 28°C than 20°C ( < 0.04). Self-paced exercise performance was maintained in 13°C and 20°C at a matched evaporative potential, impaired in 28°C, and further compromised in 36°C in association with a moderately lower evaporative potential and marked elevations in thermal, cardiovascular, and perceptual strain. This is the first study to investigate the effects of dry-bulb temperature (13, 20, 28, and 36°C) on self-paced exercise performance by minimizing differences in the skin-to-air vapor pressure gradient (i.e., evaporative potential) between conditions. Performance was similar in 13°C and 20°C with a matched evaporative potential, whereas it was reduced at 28°C and further impaired at 36°C in association with a large decrease in dry heat loss and moderate reduction in evaporative potential.
在将皮肤与空气之间的蒸气压梯度（-）差异最小化的情况下，研究了干球温度对自主运动表现的影响，以及热、心血管和感知反应。14 名训练有素的男性自行车运动员在 13°C 和 44%相对湿度（RH）、20°C 和 70%RH、28°C 和 78%RH 以及 36°C 和 72%RH 下进行了 30 公里计时赛。在 13°C（275±31W；平均值和 SD）和 20°C（272±28W；=1.00）时输出功率相似，在 36°C（228±36W）时低于 13°C、20°C 和 28°C（262±27W；<0.001），在 28°C 时低于 13°C 和 20°C（<0.001）。直肠温度峰值在 36°C（39.6±0.4°C）时高于所有条件（<0.001），在 28°C（39.1±0.4°C）时高于 13°C（38.7±0.3°C；<0.001）和 20°C（38.8±0.3°C；<0.01）。平均心率在 36°C（163±14 次/分钟）时高于所有条件（<0.001），在 20°C（156±11 次/分钟；=0.009）和 28°C（159±11 次/分钟；<0.001）时高于 13°C（153±11 次/分钟）。平均心输出量在 36°C（16.8±2.5L/min）时低于所有条件（<0.001），在 28°C（18.6±1.6L/min）时低于 20°C（19.4±2.0L/min；=0.004）。在 36°C 时，感知用力程度评分高于所有条件（<0.001），在 28°C 时高于 20°C（<0.04）。在匹配蒸发潜能的情况下，13°C 和 20°C 时自主运动表现保持不变，在 28°C 时受损，在 36°C 时进一步受损，同时伴有中等程度的蒸发潜能降低和明显的热、心血管和感知压力升高。这是第一项通过最小化条件之间皮肤与空气之间的蒸气压梯度（即蒸发潜能）差异来研究干球温度（13、20、28 和 36°C）对自主运动表现影响的研究。在匹配蒸发潜能的情况下，13°C 和 20°C 时的表现相似，而在 28°C 时降低，在 36°C 时进一步降低，同时伴随着干热损失的大幅减少和蒸发潜能的适度降低。
