Mind & Body

Muscle Memory Is Real, and That's Good News for Everyone

Whether you were a star athlete in high school or just got on a fitness kick a few years ago, it's always disheartening to get out of shape again. Getting back to that level can feel impossible when you're starting from square one. Well, we have good news: According to recent research, you may not be starting from square one after all. It turns out that your muscles remember when they were stronger, and they store that memory in their DNA.

A Methyl Group Never Forgets

When people talk about "muscle memory," they usually mean procedural memory — the brain-based memories that make it seem like your hands can just "remember" how to tie your shoe or shuffle cards without you having to consciously think about it. This isn't that. Instead, this "memory" is a record of the muscle's earlier growth, and it's actually stored in the DNA of your muscle cells.

This happens via something called epigenetics, which deals with the way your environment can influence how your genes activate. You're born with a certain set of genes; that can't be changed. But how those genes exert their influence can. Research has shown that things like diet, stress, sleep, and chemical additives can change the way certain genes are expressed, thereby causing or preventing certain traits or diseases, even in your offspring.

For a study published in the Nature journal Scientific Reports, a team led by researchers at Keele University in the UK subjected eight healthy men to a 21-week weight-training program. First, after going through one grueling resistance workout, they lifted weights three times a week for seven weeks. For the next seven weeks, they stopped exercising at all, then went through another seven weeks of three weekly lifting sessions. After each phase, researchers took muscle biopsies from their quadriceps for DNA analysis.

After examining more than 850,000 places on the men's DNA, they found that certain genes in their muscle cells were "marked" or "unmarked" with telltale chemical "tags" as the men got stronger. Those tags are what determine how particular genes are expressed, effectively turning them on or off. Importantly, those tags stayed put long after the men stopped exercising — and appeared to have an effect when the men started up again since their strength increased faster during the final seven weeks than it did during the first.

Get Your Swole On (and On, and On)

This means that exercise has further-reaching effects than we previously realized. It could mean that kids who compete in sports may have an easier time getting and staying fit in adulthood and that returning to the gym after slacking on your exercise routine could make things a lot easier than they were the first time.

But it's worrying news for those trying to ensure competitive sports aren't tainted by performance-enhancing drugs. If getting strong makes your muscles better at getting strong, then drugs might help you get a leg up on training long before it's time for a drug test.

"If an elite athlete takes performance-enhancing drugs to put on muscle bulk, their muscle may retain a memory of this prior muscle growth," said study researcher Robert Seaborne in a press release. "If the athlete is caught and given a ban — it may be the case that short bans are not adequate, as they may continue to be at an advantage over their competitors because they have taken drugs earlier in life, despite not taking drugs anymore."

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For more on how science can improve your workout, check out "TIME: The Science of Exercise: Younger. Smarter. Stronger." We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Ashley Hamer February 21, 2018

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