Thermoregulation, peripheral vessel vasomotor regulation, and hormonal responses during cold exposure in wheelchair athletes

本研究旨在了解脊髓损伤轮椅运动员在冷热环境下运动时的体温调节和生理反应特征。研究对象为脊髓损伤的男性轮椅运动员和健康男性大学生。轮椅运动员最大摄氧量作为耐力运动能力的指标高于大学生。测量环境温度为12℃和35℃，平均相对湿度为60%，平均气流为0.5m/秒。休息30分钟后，受试者进行20瓦（50转/分）的摇臂运动60分钟。测量项目为鼓室温度、平均皮肤温度、产热、儿茶酚胺和冷致血管舒张。在低温条件下运动时，轮椅运动员的鼓室温度、产热和儿茶酚胺明显高于大学生。在低温条件下，轮椅运动员的血管舒张阻力指数高于大学生。另一方面，轮椅运动员的平均皮肤温度的下降幅度比大学生要小。轮椅运动员对寒冷环境下运动的体温调节敏感性和产热反应明显高于大学生。在高温下运动时，轮椅运动员的鼓室温度、平均皮肤温度、产热和儿茶酚胺比大学生明显升高。轮椅运动员对热环境下运动的体温调节敏感性和产热反应均低于大学生。这些结果表明，脊髓损伤显著影响热环境下运动时的体温调节。

The purpose of this study is to clarify the characteristics of thermoregulation and physiological responses during exercise in a cold and hot environment in wheelchair athletes with spinal cord injury. The subjects were male wheelchair athletes with spinal cord injury and healthy male college students. The maximal oxygen intake as a parameter of endurance exercise ability was higher in the wheelchair athletes than in the college students. Measurements were performed at an environmental temperature of 12℃ and 35℃ with a mean relative humidity of 60% at a mean air stream of 0.5m/sec. After rest for 30 minutes, the subjects performed arm cranking exercise at 20 watts(50 rpm) for 60 minutes. The measurement items were tympanic temperature, mean skin temperature, heat production, catecholamine, and cold-induced vasodilation.During exercise under exposure to cold, the tympanic temperature, heat production, and catecholamine more markedly increased in the wheelchair athletes than in the college students. The resistance index as a value of cold-induced vasodilation were higher in the wheelchair athletes than college students during cold exposure. On the other hand, the decrease in the mean skin temperature was slighter in the wheelchair athletes than in the college students. The thermoregulation sensitivity and heat production responses to exercise in a cold environment were more markedly increased in the wheelchair athletes than in the college students.During exercise under exposure to heat, the tympanic temperature, mean skin temperature, heat production, and catecholamine more markedly increased in the wheelchair athletes than in the college students. The thermoregulation sensitivity and heat production responses to exercise in a hot environment were lower in the wheelchair athletes than in the college students. These results suggested that spinal cord injury considerably affects thermoregulation during exercise in a hot environment.