Who says you should stop exercising as you grow older? Why, last year, 40-year-old Eddie Hart ran 100 meters in 10.6 seconds. His contemporary, John Campbell, averaged five minutes per mile in the 1990 Boston Marathon. And 44-year-old Nolan Ryan, who just this spring pitched a record seventh career no-hitter, consistently throws his fastball at 95 mph.
If you are generally healthy and know when to stop exercising, you can exercise well into your 50s, 60s, 70s -- and beyond.
Doctors often determine how our bodies age by measuring the maximal amount of oxygen we can take in and use. Dr. Michael Pollack of the University of Florida in Gainesville has shown that older men who continued to train and compete in long-distance running races were able to maintain their maximal amount of oxygen.
This is astounding! It means that a test we have been using to measure aging actually may be measuring fitness, and that much of the aging and decline in the quality of life that comes with age may be caused more by inactivity than by aging itself.
If you're over 30, overweight, tire easily, experience shortness of breath when you get up from watching television and are too tired for your spouse, see your doctor.
Chances are, you're out of shape.
If so, start exercising. You may want to join a health club for expert instruction and access to a trained individual who will monitor your progress.
Pick two sports that stress different muscle groups and work out in those sports on alternate days. Walking, for example, focuses on your legs while working out on a rowing machine focuses on your back and upper body.
Start slowly and stop immediately if you feel pain or fatigue. Try to work up to exercising 30 minutes a day.
If you feel tired, take a day or two off. As you get older, it will take longer for exercise-stressed muscles to recover.
Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.