Use the temporary body to attain the eternal

Even though we want to keep the body fit and helpful to our activities, the body cannot continue eternally. Although I am the soul, which is eternal, after using the body for some time I have to accept another body (tatha dehantara-praptih), according to the laws of nature, unless I render some service with the body for advancement in devotional service. One should not use the body for any other purpose. One must know that if he uses the body for any other purpose he is simply wasting time, for as soon as the time is ripe, the soul will automatically leave the body.

Srimad Bhagavatam 8.22.9 purport