The late longevity researcher, Roy Walford, M.D., noted how such exercises-to-exhaustion as marathon running could shorten lifespan, a matter perhaps relevant to Christian stewardship. In his Beyond The 120 Year Diet: How To Double Your Vital Years (2000 revised and expanded Four Wall Eight Windows edition, 199), he wrote the following:
Both animal and human studies indicate that very strenuous physical exercise (exercise to exhaustion) leads to considerable oxidative stress (free radical generation) characterized by lipid peroxidation and DNA strand breakage. In humans at least, this can be inhibited or prevented by taking vitamin E (800 to 12000 milligrams daily) for three to 14 days before the exercise. Persons engaged in marathons and other exhaustive sports might wish to consider this, although the main lesson here for life-extenders may be not to undertake this kind of sport at all.
Apparently, the “bodily exercise” that “profiteth little” (1 Timothy 4:8) is moderate exercise. Immoderate exercise, on the other hand, does not offer even these limited benefits. Instead, over time, it could cause one’s death. It is far better, then, to focus most of one’s energy on spiritual exercises, on the athletics of piety, for “godliness,” unlike physical exercise, ”is profitable unto all things, having promise of the life that now is, and of that which is to come” (same verse).