Why We Sleep

Why We Sleep. Written by S. E. Virgilio. Focus question. How is sleep important to good health?

我们为什么要睡觉 作者：S·E·维吉里奥 思考问题 睡眠对身体健康有什么重要作用呢？

Introduction. It feels great to curl up between soft sheets and slowly drift off into a sound sleep. Getting a good night's sleep is important. We need sleep to function well. Like food and water, sleep helps keep us healthy and ready to go.

引言 窝进柔软的被窝，慢慢沉入甜美的梦乡，这种感觉太棒了 睡个好觉对我们来说非常重要 我们只有睡好了才能好好活动 就像水和食物一样，睡眠能帮我们保持健康，活力满满

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?

什么是睡眠呢？ 我们会在固定的时间自然地睡着 也很容易醒过来 通常只要一点声响，就能把睡着的人叫醒 所以到底什么是睡眠？ 又是什么让我们犯困睡着呢？

Doctors learned more about sleep in modern times. They studied the brains of sleeping people. The studies showed that the brain does not really shut down during sleep. It just works differently. This discovery led to more studies on sleeping brains.

到了现代，医生们对睡眠有了更多了解 他们研究了睡着的人的大脑 研究发现，我们睡着的时候，大脑其实并没有停止工作 它只是换了一种工作方式 这个发现推动了更多对睡眠中大脑的研究

Doctors wanted to know just what causes changes in brain waves. They learned that the body makes a special substance as it uses energy. During the day, more and more of this substance travels to the brain. There, it slows down the parts of our bodies that are active when we are awake.

医生们想弄清楚，究竟是什么让脑波产生变化 他们发现，身体消耗能量的时候，会产生一种特殊物质 白天，这种物质会越来越多地进入大脑 它会让我们清醒时活跃的身体机能放慢速度

The need for Z's. If our brain doesn't shut off while we sleep, what does it do? The answer. It helps us learn by storing memories. The brain must organize new information we have learned. This happens while we sleep. It's sort of like cleaning a closet. The brain sets things up to make it easier for us to remember and use what we've learned.

我们对睡眠的需求 如果睡觉时大脑没有停工，那它在做什么呢？ 答案是 它会帮我们储存记忆，方便我们学习 大脑需要整理我们刚学到的新信息 这项工作就是在我们睡觉时完成的 这有点像整理衣柜 大脑整理好一切，就能让我们更轻松地记住、使用学到的新知识