Why We Sleep

Why We Sleep, written by S .E. Virgilio. Focus question, how is sleep important to good health?

《我们为什么睡觉》，作者S.E.维吉利奥。 探究问题：睡眠对健康到底有多重要呢？

Introduction. Who doesn't like to curl up between soft sheets and slowly drift off into a sound sleep? Getting a good night's sleep is how we rest after a busy day at school, work, or play. People, and most other animals, need sleep to function well. Like food and water, sleep is necessary to keep minds sharp and bodies ready to go.

引言。 谁不喜欢蜷在柔软的被窝里，慢慢沉入甜甜的梦乡呢？ 好好睡一觉，是我们忙碌一天上学、工作或是玩耍后的休息方式。 人类和大多数其他动物都需要睡眠，才能正常运转。 就像食物和水一样，睡眠是保持头脑清晰、身体充满活力必不可少的条件。

What is sleep? Falling asleep happens naturally and at regular times. It's also easy to stop sleeping. A loud noise is often all that is needed to wake a sleeping person. So what is sleep and what makes us fall asleep? People have struggled for centuries to answer these questions. An ancient Greek thinker believed that sleep was a quiet time of rest brought on by eating. That idea is not as strange as it sounds. Most people are ready for a nap after enjoying a big meal.

什么是睡眠？ 入睡是自然发生的，且会在规律的时间到来。 醒来也同样很容易。 通常只要一声巨响，就能吵醒睡着的人。 那么到底什么是睡眠，是什么让我们入睡呢？ 几个世纪以来，人们一直在努力解答这些问题。 古希腊一位思想家认为，睡眠是进食后带来的安静休息。 这个想法并没有听上去那么奇怪。 大多数人吃饱大餐后，都想打个盹儿。

A better understanding of sleep came about in the early 20th century. Studies showed that the brain does not really shut down when people snooze. Instead, brain activity changes as wakefulness shifts to sleep. The idea that the brain remains somewhat active during sleep was new. This discovery led to more sleep research.

直到20世纪初，人们才对睡眠有了更深入的认识。 研究发现，人们睡觉时，大脑其实并没有完全停止工作。 相反，当人从清醒进入睡眠，大脑活动会发生改变。 睡眠时大脑仍保持一定活跃度这个观点，在当时是全新的。 这一发现推动了更多关于睡眠的研究。

Doctors wanted to know just what caused changes in brain waves. They learned that a substance called adenosine affects the brain and triggers sleep. The body produces adenosine naturally as it uses energy. During the day, more and more of this substance travels to the brain. There, it acts to slow down many body processes that are active when we are awake.

医生们想要弄清，究竟是什么引发了脑电波的变化。 他们发现一种叫做腺苷的物质会影响大脑，诱发睡眠。 身体消耗能量时，会自然生成腺苷。 白天，这种物质会越来越多地进入大脑。 它会在大脑中减缓我们清醒时活跃的诸多身体进程。

The need for Z's. If our brain doesn't shut down while we snooze, what does it do? The answer. It helps us learn by shuffling memories. The brain first stores much of what we learn in what is called short -term memory. Short -term memory is a good place to put information for a little while. It isn't big enough or strong enough to hold everything we learn forever. The brain must move information from short -term memory to long -term memory. This shuffle happens while we sleep. Doing this makes it easier to remember and use what we've learned.

睡眠的作用 如果睡觉时大脑没有停止工作，那它在做什么呢？ 答案是： 它通过整理记忆来帮助我们学习。 大脑首先会把我们学到的大部分内容，储存在叫做短期记忆的区域。 短期记忆适合短时间存放信息。 它的容量不够大，没法永久保存我们学到的所有内容。 大脑必须把信息从短期记忆转移到长期记忆中。 这个整理转移的过程就发生在我们睡觉时。 这个过程能让我们更轻松地记住和运用学到的知识。