Exercise pills: Should we use drugs that mimic benefits of a workout?

Researchers are developing medicines that replicate the health benefits of exercise. In the process, they’re gaining insights into how to treat currently untreatable diseases

By Jo Marchant

RONALD EVANS never intended to kick off a performance-enhancing drug craze, but that is what happened. Despite a ban on its use in sports, the substance he has long been studying has now been detected in doping tests of cyclists and boxers, while runners and bodybuilders share stories online about how it makes them leaner and stronger nonetheless.

The story begins in 2002, when Evans, a biologist at the Salk Institute in La Jolla, California, performed some experiments involving mice and exercise wheels. He fed a drug known as GW1516 to unfit mice, expecting to see modest effects on their fat metabolism. But tests showed that mice which had been given the drug could run twice as far on their wheels as ones that hadn’t. “It was an amazing moment,” says Evans. Couch-potato mice had been transformed into endurance runners. Ever since, he has been chasing a dream with ramifications not just for elite athletes, but all of us.

We know that exercise truly is the best medicine. Get your body moving, even a modest amount, and the rewards range from stronger bones to a sharper mind. But what if you could use a pill to mimic those benefits without having to do any training at all? That question – and Evans’s promising work – have sparked a drug-discovery movement. As the first fruits of this work edge closer to the clinic, there is an increasingly heated debate about how these kinds of therapies should be used. All agree, however, that a healthcare revolution is on the way.

Many of us turn to exercise as a means of …