We are involved in youth testing internationally. We want to try to prove without a shadow of a doubt the relationship between physical fitness and health, not just physical fitness and ability to perform.

So I've broadened the fitness concept to make it one of moderation and balance.

Now I say that if you run more than 15 miles a week, it's for something other than aerobic fitness. Once you pass 15 miles, you do not see much further improvement.

Far too many times over the next 12 to 15 years, it was brought to my attention that people who followed my exercise guidelines exactly but ignored their diet, their weight and their cigarette smoking had heart attacks at age 55.

The reason I exercise is for the quality of life I enjoy.