Why We Need Sleep

Most adults need between seven and nine hours of sleep every night.

大多数成年人每晚需要七到九个小时的睡眠。

Yet many people regularly get much less than that.

然而，许多人经常睡得比这少得多。

While we sleep, the brain sorts and stores what we learned during the day.

我们睡觉的时候，大脑会整理并储存白天所学的内容。

This is why a good night's sleep before an exam is so important.

这就是为什么考试前睡个好觉如此重要。

Sleep also gives the body time to repair muscles and fight illness.

睡眠还能让身体有时间修复肌肉、对抗疾病。

People who sleep badly often find it harder to concentrate and control their mood.

睡眠不好的人往往更难集中注意力，也更难控制情绪。

Over time, poor sleep can increase the risk of serious health problems.

久而久之，睡眠不佳会增加出现严重健康问题的风险。

Experts recommend going to bed and waking up at the same time every day.

专家建议每天在同一时间上床睡觉和起床。

Keeping the bedroom dark, quiet and cool can also make a big difference.

保持卧室黑暗、安静、凉爽，也能带来很大的改变。