Why We Sleep

Why We Sleep

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.

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? An ancient Greek thinker believed that eating made people sleep. That idea is not as strange as it sounds. Most people are ready for a nap after enjoying a big meal.

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.

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.

The Need for ZZZs 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.