How Much Exercise is Enough?

                          HOW MUCH EXERCISE? 2,000 IS THE MAGIC NUMBER

    My previous post on exercise economics argued for exercising efficiently—getting the biggest return on your fitness investment. Your best approach is to increase the intensity: choose a brisk walk outdoors instead of a leisurely stroll through the mall. Or lift weights instead of doing light calisthenics.

     But there are two other key factors you need to consider: volume and frequency.  How much exercise do we need and how often should we do it? Some specific answers to these questions emerged from a study of 50,000 Harvard and Penn graduates conducted over many decades by Dr. Ralph Paffenbarger.

     The results were clear. Enormous benefits in terms of overall health and reduction of mortality occurred when the participants expended 2,000 calories a week in physical activity. 3,500 calories a week conferred small additional benefits, but anything over that amount was potentially excessive.

     Paffenbarger emphasizes intensity. “The greatest benefits,” he says, “come from moderately vigorous to more intense activities….especially resistance training.” These more intense activities are critical because they boost your metabolism, reduce fat stores and add muscle. If you lost ten pounds of fat and added ten pounds of muscle, your body would burn 500 extra calories a day. Muscles make your furnace burn hotter.

     But Paffenbarger also recommends accumulating an hour a day of what he calls Stage I activities: puttering around the house, doing laundry, gardening and other chores that we take for granted. By themselves, these tasks won’t significantly improve your health, but they will burn calories. 

     So what would an ideal program look like? Three times a week, exercise for thirty minutes at a level that makes you sweat. Brisk walking, cycling, jogging, elliptical machine, treadmill—it doesn’t really matter. Two or three times a week do some form of resistance training. Weights, pushups, tubing—something that challenges your muscles. The rest of the time stay active and resist the impulse to collapse on the couch.

     Paffenbarger, I’m happy to say, is also a fan of efficient exercise. His groundbreaking study convinced him that the wisest approach is to seek “the least amount of activity needed tor the most health benefits.”  That magical 2,000 calorie a week milestone is the sweet spot. Set a goal of reaching it and enjoy much better health.