"Early to bed and early to rise makes a man healthy, wealthy and wise." This is an old English saying. It means that when we go to bed early, we can get up early the next morning. Then we will become healthy. We will also become rich and clever.
This is true. To keep healthy, we must have enough sleep. Experts say that adults should get seven to eight hours of sleep a night. Teenagers need nine to ten hours. And school-aged children may need more than ten hours of sleep. Children who do not have enough sleep can't do their work very well. They won't be wise and they may not become wealthy!
We also need exercise. Walking, running, swimming and playing games are all exercise. Exercise keeps us strong. It also helps the blood to move around the body. This is very important. Our blood takes the nutrition（营养）from food to all parts of our body.
The brain also needs blood. So take exercise and we can think better!
