高温高湿对比一般环境耐力运动对运动员肌肉疲劳的影响及相关机制

Effects of high temperature and high humidity on the fatigue of athletes in general environmental endurance exercise and related mechanisms

目的调查高温高湿应激对耐力运动、神经肌肉调节的单独和联合效应。方法简单随机抽样方法选取11名研究对象在气温/湿度适宜(对照组),高温度/湿度适宜(高温组),气温适宜/高湿度(高湿组)和高温度/高湿度[(高温+高湿)组]4个不同环境条件下,恒负荷骑车至精疲力竭。分别在运动前、后5min记录电刺激胫神经后的扭矩和肌电图反应。结果高温和高湿均缩短了运动至力竭的时间,高温高湿协同作用下的运动至力竭时间均分别低于高温或高湿组(P<0.05)。与对照组比较,高温条件下心率和皮肤温度均有升高[(9±5)次/min、和(5±1)℃,P<0.05],高湿条件下血氧饱和度明显降低[自(96±2)%降低至(88±4)%,P<0.05]。高温和高湿对运动员的核心温度或感知运动量均无显著影响(P>0.05)。高温下运动,M波、V波的振幅以及比目鱼肌或胫骨前均方根均较温和环境显著降低(P<0.05)。结论高温或高湿环境影响运动员的耐力运动能力,且两者的作用协同增加;在不同的环境条件下,肌肉疲劳的程度和特征是相似的。

Objective To investigate the separate and combined effects of high temperature and high humidity stress on endurance exercise and neuromuscular regulation. Methods Eleven physically active subjects cycled to exhaustion at constant workload (66% of the power output associated with their maximal oxygen uptake in temperate conditions) in four different environmental conditions [temperate/humidity appropriate (control),hot/humidity appropriate (hot),temperate/high humidity (humidity),and hot/high humidity (hot + humidity)]. Torque and electromyography (EMG) responses following electrical stimulation of the tibial nerve were recorded before and 5 min after exercise. Results Both high temperature and high humidity shortened the time from exercise to exhaustion,and the exercise-to-exhaustion time under high temperature and high humidity was lower than that in high temperature or high humidity group ( P <0.05). Compared with those in the control group,heart rate and skin temperature increased (9±5) times/min and (5±1)℃( P <0.05) under high temperature conditions,and blood oxygen saturation decreased significantly under high humidity conditions [from (96±2)% to (88±4)%, P <0.05]. High temperature and high humidity had no significant effect on the core temperature or perceived exercise volume of the athletes ( P >0.05). At high temperature,the amplitudes of M wave and V wave and the root mean square of soleus muscle or tibia were significantly lower than those in the mild environment ( P <0.05). Conclusion The athlete's endurance exercise ability will be impaired in a high temperature or high humidity environment,and this response is synergistically increased during combined exposure to them. In addition,the degree and characteristics of muscle fatigue are similar under different environmental conditions.