How Long Does it Take to Lose Muscle After You Stop Working Out?

Maybe it’s all the weekends away or the hot sticky weather, but there’s something about summer that makes it tough to stick to a consistent workout schedule.

Though skipping a few gym sessions won’t totally derail your weight loss efforts, going just two weeks without breaking a sweat can, recent Danish research indicates. It gets worse: In addition to taking a toll on your physique, physical fitness and strength, the findings suggest that it will take you triple the amount of time you were inactive to regain the muscle mass that you lose after a two-week fitness hiatus. (Are you running to the gym yet?)

To come to this finding, researchers gathered 17 active men in their twenties and 15 active men in their sixties. Each participant had one of their legs immobilized for two weeks. After two weeks of inactivity, all the participants lost physical fitness and muscle mass—no shocker there. However, the younger set lost about 17 ounces of muscle and 30 percent of their muscle strength (which is the equivalent of aging about 45 years, according to the study), while the older men only lost about nine ounces of muscle mass and 20 percent of their strength. Simply stated, the fitter and more muscular you are, the more you stand to lose if you slack off.

After the immobilization period, the men trained up to four times a week to regain their lost muscle mass, strength and fitness—and it ultimately took them six weeks to get back to their original shape. Apparently the old adage “use it or lose it” really does hold true.

If these findings don’t inspire you to squeeze in a few weekly workouts, we’re not sure what will. Remember, even if you can only make time to hit the gym for a half hour a few times a week, that’s better than nothing at all.