Try and avoid extreme training. Life is supposed to flow: you are supposed to feel well, not struggle. Feel the difference between "struggle" and "effort" (the latter is necessary to avoid complacency); if you struggle, you do something wrong in life and have probably not found your Life Goal.

If you aim at keeping all your life areas in balance, you will not need to run huge marathons in order to feel well. But some physical exercise in any form is a must.

If you aim for a beautiful body, check out David Kirsch's Sound Mind, Sound Body, the personal trainer of among others Heidi Klum and Ivana Trump.