Use it or lose it—until you use it again

You’re a regular at the gym. You work hard to reach your fitness goals, and your muscles reflect that! But what if you’re forced to take a break? Maybe you take a vacation, experience an injury, or maybe life gets a little too busy. Will all of your hard work go to waste?

It’s not uncommon for people to think that if muscles are left unused, they will turn to fat. While that myth has been thoroughly disproven, we also know that underused muscles will experience a gradual loss in size and structure. This lends itself to the old saying, “use it or lose it.”

However, new research suggests that this isn’t necessarily accurate, either. A study by biologists at the University of Massachusetts argues that muscles that have begun to atrophy—or shrink due to lack of use—will have an easier time returning to their previous size and strength when stimulated again.

When new muscle cells develop—from working out, in this case—there are nuclei within those cells that contain their genetic information. Muscle cells become part of a syncytium, which is a large collection of bonded cells that essentially behave like one. Other cells in the body become part of a syncytium too, like bone and heart cells.

The research shows that once a muscle cell has become part of a syncytium, the nucleus of that cell is tied to that syncytium for life. This is important because even when muscles go underused, and muscle cells begin to wither and shrink, their nuclei and all of their genetic information remain intact.

When you do stimulate that muscle again, because of the presence of these nuclei, the cells—and the muscle as a whole—will grow and strengthen more quickly.

So, the adage “use it or lose it” isn’t quite accurate—your muscles will rebound fairly quickly! Exercising regularly and stimulating your muscles is the best way to ensure that your body remains healthy and fit. The amount you’re looking to work your muscles will vary, but the best way to make certain that your muscles are consistently stimulated is to do a variety of medium-intensity exercises 2–3 times per week.