Building muscle takes years of hard work, sacrifice, and discipline. You must do countless workouts, push yourself to your limits, track your progress, eat well, and get enough sleep.
But losing muscle?
Unfortunately, that can happen much quicker, especially for people who stop training for one reason or another.
The question is, how long does it take to lose muscle if you stop training? More importantly, is there something you can do to slow down the process until you can get back to regular training?
Stick around to find out.
What Does Muscle Loss Even Mean?
Before diving into the meat and potatoes of this article, it’s essential to talk a bit about muscle loss and how it occurs.
Some people are under the impression that muscle melts off their bones if they take even a short break from training, which is not the case.
Your level of muscular development comes down to the never-ending battle between protein synthesis and breakdown. The former is responsible for accumulating proteins, whereas the latter causes us to lose proteins and muscle size.
For muscle loss to occur, the rate of protein breakdown would have to outpace muscle synthesis. In contrast, hypertrophy occurs when you experience more synthesis than breakdown. Numerous factors, including your training habits, play a role in the equation.
Now, here’s the exciting bit:
There is a limit to how much protein breakdown you can experience in a specific period. Like with fat loss, your body cannot eat through all the available tissue in a few days or weeks. These processes simply take time.
How Long Does It Take to Lose Muscle?
The good news is that muscle loss doesn’t occur nearly as quickly as some people imagine. If you skip a few sessions, you won’t shrivel up and lose all of your strength.
Sadly, muscle loss is an inevitable consequence of not working out, and you’re still bound to lose hard-earned gains.
According to some research, significant muscle loss can occur in as little as five days of not using a muscle (1). However, that likely isn’t the case for most people, and true atrophy will begin to occur after at least two to three weeks of inactivity.
In one study from 2020, researchers noted that three weeks of detraining didn’t lead to a reduction in muscle mass, strength, or sports performance in athletes aged 15 to 18 (2).
Another paper found that two weeks of detraining didn’t impact training-induced muscle or strength gain (3). In this experiment, researchers took 20 resistance-trained men and had them train four days per week.
All subjects did four weeks of training before taking two full weeks off working out. They then completed another four weeks of re-training.
The paper's authors noted that two weeks of de-training didn’t significantly impact muscle mass or strength, regardless if the subjects supplement with whey protein.
The bottom line is that short-term detraining of up to three weeks doesn’t seem to cause muscle loss in otherwise active people. By active, researchers mean everyday activities: walking, running errands, doing housework, etc.
For instance, here’s what researchers wrote in one paper (4):
Finally, evidence suggests that short (~3 weeks) periods of detraining in trained persons does not incur significant muscular atrophy and might stimulate greater hypertrophy upon return to training.
How to Reduce The Risk of Muscle Loss
The answer to “How long does it take to lose muscle?” is not clear-cut, as there are numerous factors to consider.
Regardless of where you are, there are ways to slow down muscle loss and retain as much lean tissue as possible.
1. Stay Active
You might feel that weight training is the only way to maintain muscle, but that’s not entirely the case. Being able to lift consistently is the best-case scenario, but research suggests that even everyday activity is much more beneficial than complete inactivity (i.e., bed rest) (3, 4, 5).
So, even if you’re unable to train how you want (or at all) for a while, stay active in your everyday life:
- Play some sports
- Walk more (at least 4,000-5,000 daily steps)
- Take a bike instead of driving your car everywhere
If you’re forced to take a longer break from weight training, consider high-rep bodyweight workouts at home. Push-ups, pull-ups, squats, lunges, inverted rows, and similar exercises can provide enough of a stimulus to maintain your muscle, so long as you train close enough to failure (6).
2. Eat More Protein
The most recent protein recommendations are to eat between 0.7 and 1 gram per pound of body weight daily (7). I recommend bumping your intake closer to the higher end of the range during periods of de-training.
It’s unclear if a gram per pound would be more beneficial than 0.7 grams, but it’s worth giving it a shot. More protein could support protein turnover rates better, slowing down the rate of muscle loss.
3. Consume Enough Calories
In addition to eating enough protein, you should also get enough calories and avoid any dieting phases while not training.
Combining a calorie deficit with no training is the perfect recipe for muscle loss because your body would readily break down lean tissue for energy.
A simple way to tell if you’re at maintenance is to weigh yourself four to seven times per week and calculate your average from week to week. If it’s staying relatively the same, you’re likely at maintenance.
4. Get Enough Sleep
The final factor in answering “How long does it take to lose muscle?” is sleep.
Though it may not seem so, the duration and quality of sleep you get will profoundly impact your physique, whether you train consistently or take a break from the gym.
First, there is a correlation between sleep quality and testosterone levels. According to some data, not getting enough sleep can decrease testosterone levels, which could affect your fitness outcomes (8).
Second, poor sleep can affect decision-making and increase cravings, making you more likely to eat junk food instead of whole and nutritious foods. As a result, you might not get enough quality protein, which is crucial for maintaining muscle mass.
Third, there is a significant behavioral component to sleep. Getting adequate rest at night could lead to higher energy levels and a sense of well-being. Feeling better would mean you’re more likely to engage in physical activity, even if it isn’t structured exercise.
Finally, there is a direct link between sleep quality and muscle protein synthesis. While we certainly need more research here, data suggests that sleep deprivation increases the risk of protein degradation and catabolism (9).
So, try to get at least seven hours of uninterrupted sleep every night. Even if it doesn’t make a big difference, adequate sleep is crucial for overall health and well-being.
The Silver Lining
The silver lining in all this is that, even if you lose some muscle because you have to take a break from training, it is much easier to rebuild it and return to where you left off. All of this is possible thanks to a neat little thing called muscle memory.
(It’s worth noting that the research behind muscle memory is inconclusive, and scientists don’t fully understand how or why things work.)
The leading theory illustrated in a 2010 study is that myonuclei accumulated in muscle cells during training stick around forever (10). So, even if a person stops training and loses muscle size, the myonuclei would remain, making it easier to rebuild all the lost muscle in a fraction of the time.
However, a more recent study has different findings. In it, 53 older men completed a 24-week resistance program (11). The participants were then not instructed to continue exercising after the experiment.
A year later, all the participants were contacted and invited to return to the lab for some tests. Of the 53 participants, 35 came back and were split into two groups:
- Group 1 - 16 individuals who continued to exercise after the experiment
- Group 2 - 19 people who didn’t do any structured exercise after the study
Unsurprisingly, subjects in Group 1 maintained more strength and muscle than their sedentary counterparts. What’s more interesting is that myonuclei content in type 2 muscle fibers had returned to baseline after one year of de-training.
Here’s a quote from the paper:
In response to the RT program, type II muscle fiber myonuclear content increased significantly and returned to baseline at the 1 y follow-up assessment.
While we don’t understand exactly why muscle memory occurs, we know that it does, and there is some rationale behind this bodily function.
Muscle is metabolically costly, which, from an evolutionary standpoint, isn’t great for our survival. More muscle means a greater energy expenditure, which could make it more challenging to consume enough calories during periods of food shortage.
So, the human body keeps the muscle it needs and breaks down the rest to limit the energy expenditure and put us in a better position for long-term survival. With that said, the body also needs a way to regain lost muscle more quickly if necessary, which is where muscle memory comes in.
There isn’t a straightforward answer to the question, “How long does it take to lose muscle?” Multiple factors play a role in the equation, including nutrition, sleep, lifestyle, age, etc.
The good news is that muscle atrophy takes longer to occur than most people imagine. Taking a couple of weeks away from the gym doesn’t mean you will lose muscle or strength.
Fortunately, it is much easier to rebuild lost muscle even if you have to take a longer break from the gym due to injury, illness, or something else. It might have taken you a few years of training to attain your physique, but you could return to your previous form in just a few months.
So, don’t worry too much about it. Train consistently, but know that you can regain lost muscle relatively fast when you return to structured training.