I have lately found myself bombarded with pressure to exercise. Part of it is New Year’s resolutions, to be sure, but even the scientific literature has joined the lobbying effort. In October, the British Medical Journal published a review article suggesting that exercise and drug treatment were similarly effective at preventing heart disease mortality. Coverage of this study touted the benefits of exercise, with headlines like “Exercise ‘as good as medicines’ in treating heart disease.” Even Slate got on the bandwagon, arguing that exercise is a “free and readily available” way to treat many diseases.
The policy argument, either explicit or implicit in these pieces, is that doctors should spend more time encouraging their patients to exercise. Or they should consider prescribing exercise rather than drugs to treat some conditions. Or that we as a society should pay people to exercise. Really, anything to get people to exercise more because, it seems, exercise is a cheaper way to deliver the same health benefits you’d get from drug treatment.
As an occasional exerciser, I appreciate the opportunity to feel more virtuous when I get around to working out. But as an economist, I can’t help but feel like this is a little backward.
The first thing to say is that exercise isn’t actually free. Even if you ignore the gym membership and forgo cute yoga pants, exercise takes time. And because your time has value (or, in a technical term, there is an “opportunity cost”), it is expensive to exercise even if all you do is put on your ratty old gym clothes and run around the block.