Endurance drug makes mice run for 70% longer

Right now, if I pushed myself, I could probably run a 10km race, given I did so 18 months ago. But if an “exercise in a pill” drug has the same impacts on humans as it seems to do on mice, I’d be able to go for nearly 17km without any training. Sign me up.

Scientists from the Salk Institute found that administering a drug known as GW1516 for eight weeks led to laboratory mice that were able to run on a treadmill for 70% longer than mice that hadn’t taken the drug. The average time went from a pretty impressive 160 minutes to a whopping 270 minutes before their mousey blood sugar levels dropped to 70mg/dl.

“It’s well known that people can improve their aerobic endurance through training,” explained senior author Ronald Evans. “The question for us was: how does endurance work? And if we really understand the science, can we replace training with a drug?”

So how does this shortcut to stamina work, and why does it seem to do such a good job of emulating a gruelling training programme? GW1516 (which you should probably know is sold on the black market as a performance enhancing drug) seems to work by activating PPAR delta (PPARD) – a gene pathway that stops sugar being used as the energy source for exercise and makes the muscles favour fat instead.

Interestingly, the improved performance of the mice that took the drug wasn’t matched by the typical physical changes that occur from training: there were no additional mitochondria, no extra blood vessels and no shifts in the muscle fibres themselves. On top of this, the mice that took the drug were less inclined to gain weight and were more responsive to insulin – both qualities we typically associate with physical fitness.

“Exercise activates PPARD, but we’re showing that you can do the same thing without mechanical training,” explained the study’s lead author Weiwei Fan. “It means you can improve endurance to the equivalent level as someone in training, without all of the physical effort.”

There’s one giant caveat here: mice aren’t humans. You can’t assume that any drug that works wonders on rodents will do the same for us bipeds. But if the impact on humans is equally dramatic, then we could be looking at a brilliant way to increase stamina in the elderly, disabled or obese – groups that are often unable to exercise. Pharmaceutical companies are apparently keen to run human trials, so watch this space.

Images: Frankieleon and Salk Institute/Waitt Center