In 1490, Ponce de Leon set out to find the fountain of youth. He didn't find it, and now, more than 500 year later, the only mechanism ever found to prolong life and delay aging is exercise. There is no data whatever to show that antioxidants, vitamins, or anything else prolong life. All tests that are used to measure aging really measure physical fitness. A fit 70-year old will score younger on aging tests than an out-of-shape 20 year old.

Scientists measure aging with a test called VO2max, your maximal ability to take in and use oxygen. Studies from Ball State University, Courtland State, Washington University in St. Louis and Mt Sinai Medical Center in Milwaukee show that intense exercise maintains fitness. People who do not exercise lose 15 percent of their fitness per decade, those who exercise at low intensity lose nine percent, while those who exercise intensely barely lose any fitness at all.

In the 1930s, Fred Wilt was an Olympian distance runner. At age 50, he was able to run two miles in less than ten minutes. Those of you who run competitively know that this is a magnificent time and that there are very few high school runners who can run faster than that. He was able to run a 9:40 two mile on training of only five to seven a week, by alternating almost flat-out 200 meter runs with jogging until recovery.

Increasing intensity makes you fit. If you go out and jog the same two miles at the same pace every day, you will not improve and you will not be very fit. However, if you run faster on one day, feel sore on the next day, and then run slowly until the soreness disappears, and then run fast again, you will be able to run faster, become more fit on every measure of fitness, and also test better on the tests that measure aging.

However, with increased intensity comes increased risk of injury. So, before you start an intense exercise program, and before you start lifting heavier weights, running faster, jumping, higher, throwing further, hitting a tennis ball harder, or doing anything that requires increased intensity, check with your doctor. The only problem with this recommendation is that the odds are overwhelming that your doctor won't know very much about sports, training, or improving physical fitness. But you should at least check with him or her to see if you have a condition that can be aggravated by hard exercise. Also remember that older people can't train intensely very often. You may have to wait two to ten days between hard workouts.