Faculty of Health Care Sciences, Himeji Dokkyo University, Himeji, Hyogo, Japan.
National Institute of Technology, Akashi College, Akashi, Hyogo, Japan.
J Strength Cond Res. 2019 Oct;33(10):2608-2615. doi: 10.1519/JSC.0000000000003260.
Otani, H, Goto, T, Goto, H, Hosokawa, Y, and Shirato, M. Solar radiation exposure has diurnal effects on thermoregulatory responses during high-intensity exercise in the heat outdoors. J Strength Cond Res 33(10): 2608-2615, 2019-This study investigated the diurnal effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during high-intensity exercise in the heat outdoors. Ten male high school soccer players completed two 2-hour soccer training sessions under a clear sky in the heat of summer. These sessions were commenced at 0900 hours (AM) and 1600 hours (PM) on separate days. Solar radiation and elevation angle were higher in AM (820-1,070 W·m and 45-69°) than PM (620-110 W·m and 34-10°: both p < 0.001). Neither ambient temperature (AM 29-32° C; PM 31-31° C) nor wet-bulb globe temperature was different between trials. Although mean skin temperature was not different between trials, infrared tympanic temperature was higher at the end of exercise in AM than PM (p < 0.001). Heart rate (p < 0.01) and body heat gain from the sun (p < 0.001) were greater during exercise in AM than PM. Dry heat loss was smaller, but evaporative heat loss was greater in AM than PM (both p < 0.001). Thermal sensation and rating of perceived exertion were similar between trials, but GPS measurements showed a less total distance and distance covered by walking, jogging, and running in AM than PM (p < 0.01). This study demonstrates a greater thermoregulatory strain in AM than PM during 2-hour high-intensity soccer training in the heat under a clear sky. This observation is accompanied by a progressive increase in environmental heat stress with rising solar radiation and elevation angle in AM and a greater body heat gain from the sun in AM compared with PM.
大谷、后藤、后藤、细野。户外高温环境下高强度运动中，太阳辐射的日变化对体温调节反应有影响。J 力量与条件研究 33(10):2608-2615，2019-本研究调查了与太阳仰角变化相关的太阳辐射日变化对户外高温环境下高强度运动中体温调节反应的影响。10 名男性高中足球运动员在夏季炎热天气下分别在两个晴朗的日子里完成了两次 2 小时的足球训练。这些训练分别在上午 0900 点（上午）和下午 1600 点（下午）开始。上午的太阳辐射和仰角较高（820-1070 W·m 和 45-69°），而下午的太阳辐射和仰角较低（620-110 W·m 和 34-10°：均 p < 0.001）。环境温度（上午 29-32°C；下午 31-31°C）和湿球温度在试验中没有差异。虽然试验中平均皮肤温度没有差异，但在上午运动结束时红外鼓膜温度高于下午（p < 0.001）。上午运动时心率（p < 0.01）和太阳辐射引起的体热增加（p < 0.001）大于下午。干热损失较小，但上午的蒸发热损失大于下午（均 p < 0.001）。热感觉和感知努力评分在试验中相似，但 GPS 测量显示上午的总距离和步行、慢跑和跑步的距离小于下午（p < 0.01）。本研究表明，在晴朗天空下户外高温环境中进行 2 小时高强度足球训练时，上午的体温调节应激大于下午。这种观察结果伴随着环境热应激的逐渐增加，上午随着太阳辐射和仰角的升高，太阳辐射引起的体热增加也大于下午。
