Many folks think of middle age as the span between 40 and 60. Anyone wending their way beyond that has been considered old. I thought so, too, until I ran past the 60 mark myself many years ago.

Today, we see a paradox going on. Though many Americans are letting obesity usher them into an older age too soon, whole gym-fulls of others are stretching those 40-to-60 numbers. Remember when no one could run a mile in less than four minutes? Now we have a 42-year-old who has covered that distance in three minutes and 58 seconds. A 50-plus fellow has pole-vaulted 15½ feet, a height no one had reached until the 1940s (OK, the flex pole has helped -- but that's still high off the ground.) And get this: a 100-year-old man has run a full marathon; that's 26.2 miles, my friends! Not wanting to neglect those who exercise in swimming pools, I note that Richard Abraham, age 60, clocked just more than 49 seconds racing 100 yards in the water.

We can't all be champions like those individuals, but they should inspire the rest of us to get off the couch, out the door and onto the running, biking or skating paths or at least into a gym to tone up a few muscles. Recent studies have indicated that even a modicum of physical exercise can help stave off some of the bad stuff that can come with advancing years: Alzheimer's, dementia and similar life-ruiners.

Well, that's the body. We promise to take better care of it!!! Now for the head office directing all this activity. Neurons, axons and dendrites in the brain need exercise, also. Most people go through workaday lives at jobs keeping their thinking-caps pretty busy. Yet, even they can benefit from leisure activities that force brain cells into serious action.

Over the years, this writer has enjoyed the challenges of chess, checkers, solitaire, crosswords and magazine quizzes. I'm good at chess, but sportswriter Bill Kruissink and others have checkmated me into humility several times. Nevertheless, I still come back for more. As readers of the column know, making lists is an interesting activity we can do by ourselves: 10 best presidents; 10 poorest ones; best heavyweight prizefighters (Louis is first, Ali about fifth or sixth); most beautiful places visited -- Yosemite tops that list.

Gym workouts were mentioned earlier. Here's where cross-training comes in. For one thing, if a runner doesn't have strong abdominal muscles, he or she won't be among the leaders in most races regardless of the distance. The upper body is as important as the legs in running. As George Burns put it, keeping yourself booked and busy is far better than just sitting around in the home comparing operations and food stains on your clothes.

Note: Joe King holds the world outdoor mile record (7:09) for anyone older than 80.

Contact Joe King at alamedanews@bayareanewsgroup.com.