An experimental drug touted as “exercise in a pill” has dramatically increased endurance in couch potato mice, even after a lifetime of inactivity. It appears to work by adjusting the body’s metabolism, allowing muscles to favor burning fat over sugar, researchers report in the May 2 Cell Metabolism.
Sedentary mice prodded into exercising ran for an average of about 160 minutes on an exercise wheel before reaching exhaustion. But mice given the drug for eight weeks could run for 270 minutes on average. These mice were burning fat like conditioned athletes, even though they had spent their whole lives taking it easy, molecular biologist Michael Downes and colleagues found.
Normally, running, cycling or other prolonged exercise eventually depletes available glucose in the blood, leaving the brain short of energy.