人在一生中,都有过非自觉地打呵欠和仲懒腰的体验。打呵欠、伸懒腰,多在用脑过多、疲倦、睡眠不足的睏顿时出现,一些患有慢性病体质不佳的人,也易频频出现。究竟人为什么打呵欠、伸懒腰,医学生理学界一直认为是脑与血液缺氧,形成的呼吸动作。但迄今,未见有可靠数据,说明打呵欠和伸懒腰时,体内二氧化碳排出与胸腔增氧;特别是人到老年不爱打呵欠,精神病患从不打呵欠,也不伸懒腰,不能说这些人脑与血液中含氧总那么充裕。美国马里兰大学的罗普文对打呵欠、伸懒腰这两个生理性反应进行了一系列试验研究。他发现,呼吸并不是其首要功能,打呵欠 In life, people have had the experience of involuntarily yawning and soothing. Yawning, stretching, and more in the brain too much, tired, lack of sleep when the emergence of some people with chronic diseases of poor health, but also easy to frequent. Why people yawning, stretching, medical physiology has always been that the brain and blood hypoxia, the formation of respiratory movements. However, so far, no reliable data have been found indicating that when the body yawns and stretches, carbon dioxide is excreted in the body and oxygenation in the thorax is increased. In particular, people do not love yawning when they are old, and mental patients never yawn or stretch, Brain and blood oxygen in the total so abundant. Rowen at the University of Maryland in the United States conducted a series of experimental studies on the two physiological reactions of yawning and stretching. He found that breathing is not its primary function, yawning