南京脑科医院老年神经科副主任、医学博士张丽表示,目前医学上认定打哈欠是由脑部缺血、缺氧造成的,跟脑干和下丘脑有关。“打哈欠的时候,肺部扩张,心脏交换血液增加,血液中的含氧量就会增加,打哈欠就是大脑缺血缺氧的一个信号。反应过程简单说来是大脑缺氧,反应到下丘脑,表现出打哈欠的症状。”张丽说,同时打哈欠也是一种增加大脑血氧含量的短暂自我保护,所以日常的打哈欠其实是一个好 Nanjing Brain Hospital Department of Geriatrics, deputy director, MD, said Zhang Li, currently identified as yawning medicine is caused by cerebral ischemia, hypoxia, with the brainstem and hypothalamus. “Yawning, the expansion of the lungs, increased blood exchange in the heart, oxygen levels in the blood will increase, yawning is a signal of cerebral ischemia and hypoxia. The reaction process is simply the brain hypoxia, the reaction to Hypothalamus, showing symptoms of yawning. ”Zhang Li said that while yawning is also a temporary increase in cerebral oxygen content of self-protection, so the daily yawn is actually a good