Early-morning Shivers
清晨为何冷得发抖？
自然界、生物界都有它本身的特有的严谨的节律。人体的生物节律与自然节律相适应，人类才得以生存下来。地球上亿万年的昼来夜往，永不停息。人体的各种生理机能随之建立了有规律的昼夜周期，睡眠和醒觉节律就是一例。人体的一些生理活动昼夜之间有周期性变化。人的体温早晨稍低,白天逐渐上升,到黄昏又高一些。这些生理变化，一天之中的波动范围是恒定的，周期和时钟相似。。人类习惯于白天工作夜晚睡眠，一天24小时，8小时工作，8小时睡眠，与之相适应的是人的机体白天适宜于活动，夜晚身体机能使白天产生的变化得以恢复。
If you’ve ever stayed up the whole night through, you may have noticed that you begin to feel cold in the hours just before morning.
如果您有通宵熬夜的经历，您就会发现，在清晨前的几个小时才会开始觉得冷。
Supposing you normally go to sleep at eleven o’clock, on the night that you stay awake the shivers will hit you somewhere around four or five a.m. — just about the time when you might otherwise pull up an extra blanket and sleep for another few hours. Although people often assume that the shivers come at the coldest part of the night, the actual explanation is found within the body itself.
假如您平常11点睡觉，在你醒着那晚的清晨4,5点，猛的一下您会冷得直哆嗦，熟睡时的夜晚，您就得拉来另外一床毯子，再睡几个小时。人们想当然的认为是在夜晚最冷的时候会哆嗦，然而真正能解释的是人体自身。
Sleep is one way of conserving energy. During the night, when we are inactive, it isn’t necessary to generate as much energy as we need for our daily business of moving around, finding food, and so forth. So, instead of maintaining the same temperature all day, which would waste a lot of our energy, our body temperature rises and falls in accordance to what is needed. This kind of pattern is called a circadian rhythm, because it takes one day to complete before starting over.
睡眠是节约能量的一种方式。晚上的时候，我们不会活动，就没有必要产生如日常行动以及寻找食物等所需要的那么多能量。一整天维持同样的体温需要耗费大量的能量，因此，体温会按照需要不断的升降。这种模式因其从始至终变动的周期为一天24小时而被被称作昼夜节律。
The circadian temperature rhythm continues to run, regardless of whether you yourself have decided to go to sleep or not. Your body, you might say, executes the same strategy for conserving energy during what were supposed to be your off-hours. Your internal temperature descends to its lowest point late at night when you would normally have been in deep sleep. This conservation-mode is experienced by you as a creeping sensation that the room is getting colder and colder, when in fact it is your own body that is generating less and less heat.
无论是是否睡觉，体温昼夜变动照样进行。您可能会说，您自身机体在您所自认为的休息时间也能实行节能策略。通常，体内温度达到最低点是在夜里熟睡之时。这种节能模式你感觉起来像是房间变得越来越冷，而实际上是您的机体产生的热量越来越少。
Do this for several nights in a row, and your temperature rhythm will begin to adjust itself. But anytime you keep yourself awake when the body expects to be asleep, those early-morning shivers will return.
连续几晚上熬夜，体温节律就会开始自行调整。不过，在您醒着，而身体希望睡觉的时候，清晨那一阵哆嗦是免不了的。 |