春天来了,春云舒卷、春光明媚。可是,有许多人在春天里常常感到身体困倦,懒动爱睡,这是什么原因呢?原来,在我们的身体里有一架复杂而又精密的“生物钟”。它每时每刻都在运转。大脑神经的兴奋和抑制,睡眠与觉醒,体温的高低,心跳的快慢,血管的收缩与舒张,激素的分泌等生物节律,都受生物钟的控制和影响。春天来临时,阳气上升,外界气温随之增高。这时,人体不能马上适应季节交替的变化,生物钟的节律会发生紊乱。同时,机体为了散发多余的热能,体表的末梢血管便会舒张,使流向体表皮肤的血流量增加,脑组织得到的血液和氧气相应减少,以致发生缺氧现象。这样,人们就感到疲乏身困,爱睡觉。此外,春季人体内的激素 Spring is coming, spring cloud Shu volume, bright spring. However, many people often feel sleepy and sluggish in spring, what is the reason? In fact, there is a complex and sophisticated “biological clock” in our body. It is running all the time. The brain’s nervous excitement and inhibition, sleep and wake, body temperature, heart rate, vascular contraction and relaxation, hormone secretion and other biological rhythms are subject to the control and influence of the biological clock. When spring comes, the yang rises and the outside temperature increases. At this time, the body can not immediately adapt to changes in the seasons, the circadian rhythm disorders. At the same time, the body in order to distribute excess heat, peripheral blood vessels of the body surface will be diastolic, so that the blood flow to the body surface and skin increased, the brain tissue to reduce the corresponding blood and oxygen, resulting in hypoxia. In this way, people feel tired and sleepy, love to sleep. In addition, hormones in the spring human body