At a recent dinner party, a geeky friend of mine was cheerily justifying the piles of money he spends on a personal trainer. He’s feeling so great that it’s worth every cent, he exulted, “And the best part is the return on the time! Every minute you spend working out comes back to you, because you’ll live that much longer!”
“Really?” I wondered. I knew vaguely that being active lengthens life expectancy, but was the return on time spent really 1 to 1?
Certainly, I hoped it was. It’s a daily struggle to make the time to exercise, and the current federal health guidelines call for at least 150 minutes a week of moderate exercise — a lot of time that somehow manages to seem like even more, magnified by the “should” it adds to so many days. There are hundreds of other reasons to exercise, and the one that works best for me is wanting to feel at my best on that very day. But it would be very comforting, I thought, if I knew that all of that time would come back to me.
Let me cut to the happy conclusion: It seems that it does. And then some. If you play with the data of a recent major paper on exercise and longevity, you can calculate that not only do you get the time back; it comes back to you multiplied — possibly by as much as seven or eight or nine.
To quote Tom Anthony, a regular CommonHealth reader with a Harvard physics degree who kindly helped me with the math, “I wish I could get these paybacks in the stock market.”
This is all a bit of a public health parlor game, of course, resting on averages and approximations. You, personally, could work out ten hours a week and still die flukishly young. But the math looked so striking that I asked for a reality check from Dr. I-Min Lee of Brigham and Women’s Hospital, a Harvard professor and senior author of that recent paper, “Leisure Time Physical Activity of Moderate to Vigorous Intensity And Mortality: A Large Pooled Cohort Analysis.”
Yes, she confirmed, she had not calculated out the question before, but according to her data, a middle-aged person who gets the recommended 150 minutes per week of moderate exercise — defined as the level of brisk walking — can expect a 1-to-7 return: seven extra minutes of life gained for each minute spent exercising.
Some background: Continue reading