Too many widows wrote and told me about so and so who followed my guidelines but had a heart attack. So I've broadened the fitness concept to make it one of moderation and balance. There are six components of wellness: proper weight and diet, proper exercise, breaking the smoking habit, control of alcohol, stress management and periodic exams.
Second, you can run a good thing into the ground. I used to think that it didn't make any difference how far you ran if you had a good, strong musculoskeletal system and no underlying cardiovascular problems. Run ultramarathons if you want. 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. It takes a tripling of the number of miles to get any minimal improvement in oxygen consumption. And there's an exponential increase in injuries. So, again, moderation and balance. Once you get to 15 miles, you're at the 95th percentile level; you've got only 5 percent of potential left.
