Everyone hopes to live happily in the world. Physical exercise is indispensable to a happy life. There is a famous saying: "Life lies on exercise." Although you will not necessarily die without regular physical exercises, they'll certainly help you live longer and more healthily.

Exercise is good for us to build our bodies. It helps coordinate the different parts of our bodies when we have sports. For example, we must try our best to coordinate the movements of the arms and legs when we play basketball, or we won't be able to shoot the basket. Exercise also benefits our organs. It lets the heart beat faster than usual, and then helps enlarge the blood vessels to protect us from heart attacks.

Exercise can also contribute to the development of our ability to response agilely. For instance, when you play table- tennis, you must try to reflect as quickly as you can so that you may fight back at the right position at the fight moment.

Exercise can also contribute to improving our mood. When you do exercise, you move a lot, and you have to be more active. It helps you become more optimistic.

Exercise will fill your life with various contents and make it more colorful.

What's more, exercise will help you get rid of your inertia. If you keep doing exercise regularly, you will never be a lazy person. Therefore, exercise has great effect on one's character.

In a word, exercise is helpful, important and absolutely necessary.

每个人都希望幸福地生活在这个世界上。对于幸福生活体育锻炼是必不可少的。有一句名言：“生命在于运动”。虽然没有规律的体育锻炼你不一定会死，但是体育锻炼能帮助你活得更久，更健康。

锻炼对我们的身体很好。运动的时候能够帮助我们 协调身体的各个部分， 例如，打篮球的时候我们必须尽力使手脚协调，否则我们不会投中篮。运动也有利于我们的器官。它让心跳比平时快，然后帮助扩大血管来预防心脏病。

运动也有助于提高我们的反应能力。例如，打乒乓球时你必须要快速反映，这样你才可以在正确位置反击。

运动也有助于改善我们的心情。做了运动，活动多了，你也会变得更活跃。它可以帮助你变得更加乐观。

锻炼会使你的生活变得丰富多彩。

而且运动可以帮助你摆脱你的惰性。如果你经常锻炼，你永远都不会成为一个懒惰的人。因此，运动对一个人的性格有很大的影响。

总之，运动是很有用，很重要，当然也是很有必要的。