呼市王正祥先生: 正常人在睡眠不足或疲劳时会打哈欠,因哈欠的深呼吸作用可增加氧的吸入,使人暂时减轻疲劳。可是,中老年人,尤其是患有高血压、脑动脉硬化者如频频打哈欠,应警惕为缺血性中风的先兆。 大量病例观察表明,大约有70％～80％的缺血性中风病人在发病前一周左右因大脑缺血、缺氧而出现打哈欠的现象。其原因是中老年人,特别是高血压、脑动脉硬化患者,由于动脉粥样硬化,血管腔变窄,血管弹性降低,以致流向大脑的血液相对减少。虽然大脑的重量仅占体重的2％左右,但其耗氧量却 Mr. Wang Zhengxiang, Hohhot: Normal people will yawn in lack of sleep or fatigue. The deep breathing effect of yawn can increase the inhalation of oxygen and make people temporarily relieve fatigue. However, the elderly, especially those with high blood pressure and cerebral arteriosclerosis who frequently yawn, should be alert to the harbingers of ischemic stroke. A large number of case observations showed that about 70% to 80% of ischemic stroke patients yawning due to cerebral ischemia and hypoxia about a week before onset. The reason is the elderly, especially in patients with hypertension and cerebral arteriosclerosis, due to atherosclerosis, narrowing of the blood vessel, decreased blood vessel elasticity, resulting in a relatively reduced blood flow to the brain. Although the weight of the brain accounts for only 2% of body weight, but its oxygen consumption