Ecclesiastes 11:10

10 So then, banish anxiety from your heart and cast off the troubles of your body, for youth and vigor are meaningless.

Read Ecclesiastes 11:10 Using Other Translations

Therefore remove sorrow from thy heart, and put away evil from thy flesh: for childhood and youth are vanity.
Remove vexation from your heart, and put away pain from your body, for youth and the dawn of life are vanity.
So refuse to worry, and keep your body healthy. But remember that youth, with a whole life before you, is meaningless.