Here’s how long it can take to build muscle back after time away from the gym

The holiday season can make it difficult to stick to your fitness program, and it’s normal to worry about losing your gains. The good news is that taking a break from the gym probably won’t wipe out your progress.

That’s according to a new study showing that people who took a 10-week break from resistance training maintained their muscle growth, strength and vertical jump performance when they started training again.

“Our results therefore suggest that, during lifelong strength training, exercisers should not worry too much about occasional, short-term training breaks in everyday life,” write the authors in the study published in the journal Scandinavian Journal of Medicine and Science in Sport.

Here’s what you should know about the research, why your hard-won gains may last longer than you think, and whether experts recommend taking a break from training.

To test how a break from training after several months of resistance training affects peak strength and muscle size, researchers at the University of Jyväskylä recruited 55 relatively healthy men and women aged 18 to 40. None of the participants had a long history of resistance training before studying.

Participants were randomly divided into two groups: one that performed resistance training exercises such as bicep curls, squats and lunges twice a week continuously for 20 weeks, and another that took a 10-week break halfway through.

Researchers measured participants’ muscle strength and size before the study and every fifth week after it began, except during the 10-week break.

Researchers found that participants who took a 10-week break in the middle of their training experienced similar gains in muscle strength and size as those who trained continuously. They also found that both groups made similar progress, as their strength and muscle size quickly returned to pre-break levels once they started training again.

“In the first few weeks after the break, progress was very rapid, and after just five weeks of retraining, the level before the break was already reached,” said Eeli Halonen, lead author of the study and a doctoral student in the Faculty of Sport and Health Sciences, said it in a statement.

“With continuous group training over 20 weeks, progress slowed significantly after the first 10 weeks,” said Halonen. “This meant that there was ultimately no difference in muscle size or strength development between the groups.”

The research supports the findings of previous studies on the effects of training breaks, including one from 2020 that found there were no significant effects on muscle thickness, strength or athletic performance after stopping resistance training for three weeks in teenage athletes.

The new study left some questions unanswered, but Ryan Glatt, CPT, NBC-HWC, certified personal trainer, brain health coach and director of the FitBrain Program at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California, tells Health.

It’s unclear “how longer rest periods or different intensities might affect the results,” he noted, and the study’s focus on untrained individuals also limits its relevance to experienced lifters, who may be more able to adapt after a break, he said Smooth. While body and type of training can influence results, people who train longer and harder tend to bounce back quicker.

During a break, you may not lose as much progress as you expect because when you exercise regularly, your muscles undergo changes such as increased blood flow, which make it easier to regain strength after a break, Alan Beyer, MD, a board-certified orthopedic surgeon specializing in knee surgery and sports injury treatment at the Hoag Orthopedic Institute Health.

“When you lift weights regularly, you improve blood flow to these muscles, making them stronger,” Beyer said. “Because these muscles already have better circulation and blood supply and are able to work harder without starving their blood flow fibers, it takes a long time for these blood vessels to shrink and die if the muscle is not used.”

Previous training also improves the muscle cells and neural pathways for movement, Glatt added, both of which “make it easier to rebuild strength and muscle after a break.”

These changes are what people refer to when they talk about “muscle memory,” which Beyer says is the ability of your muscles to “remember movements and actions that you have performed repeatedly in the past.”

For example, when you practice lifting weights or hitting a baseball, your brain and muscles work together to make that movement easier over time. Even if you stop doing that activity for a while, your muscles remember how to do it when you start again, and you usually get back to it quicker than when you started.

Something similar happens when you take a break from cardio exercise, which stimulates the heart, lungs and energy-producing parts of cells called mitochondria, Glatt said. They can “recover more quickly after retraining because of the retained efficiency of these systems.”

“It’s important to note that the effects of a break ultimately depend on the duration and your training history,” Glatt said. For example, short breaks of one to two weeks typically have little impact on progress, especially for experienced lifters, Glatt added. On the other hand, longer breaks, especially months-long breaks, tend to lead to larger losses, especially for beginners.

Glatt said that as long as you train consistently, it typically takes about half the rest length to get back to your previous fitness level – which is consistent with the results of the new study. “For example, a six-week break might require three weeks of training to regain previous levels of strength and size,” he said.

When it comes to building muscle mass again, it may take longer than the study results suggest, Beyer said. As a general guideline, every week that you’re not training or immobilized, it takes about three weeks to recover and get back to your previous level, he explained. For example, if you wore a cast for six to eight weeks due to a fracture, it may take 18 to 24 weeks to regain all the muscle mass you had before the injury.

According to Glatt, planned breaks from your regular training program can help reduce the risk of overtraining and allow for recovery without major setbacks. These occasional breaks can also reduce the risk of injury and help optimize performance.

While it makes sense to take a week’s break every few months, Glatt says the exact length and frequency of your breaks will depend on your individual needs and the intensity of your training.

The key is “listen to your body,” Beyer added. If you’re feeling pain or dealing with an injury, it’s okay to take a few days off to rest and recover.