How Fast Do You Lose Muscle When You Stop Training?


Given how hard it is to build significant amounts of muscle during long stretches of focused and extensive training, you’d think it would be only fair that you would keep that muscle for at least as long during layoffs from training. Alas, however, the physique gods are not nearly so forgiving.

In fact, it can be amazing just how quickly you lose muscle mass during inactivity. Even short terms breaks of relative inactivity can have compromising effects. In a 2016 study published in the journal Diabetes, researchers studied the effects of just one week of bed rest on otherwise healthy, well-trained young males. The results were startling. Bed rest resulted in an average loss of 1.4 kg (3.1 lbs) of lean tissue mass for the males, with related losses in strength and an increase in whole body insulin resistance. Three pounds! Think of how long it takes to build that kind of mass!

Similarly, in a Danish study published in the Journal of Rehabilitation Medicine, researchers found that active young men lost 28% of strength in leg muscle after two weeks of immobilization with a cast, as well as an amazing 17 ounces of muscle mass.  Worse yet, returning to previous levels of training volume for six weeks and longer did not entirely restore the athletes' previous strength levels or muscle mass.

Finally, in another study, published in 2013 in the International Journal of Preventive Medicine, researchers studied the effects of strength training and short-term detraining on women aged 50 and over. Strength training over a period of 12 weeks had predictable effects, yielding significant increases in 1 RM for bicep curl, trunk flexion and other movements. They then studied the effects of a 4-week detraining period on the same group. Subjects in the group experienced a significant adverse effect on muscle power, as well as increases in fat mass and decreases in skin fold thickness.


Best Muscle-Building Protein Formula On Sale

Researchers have also noted that cardiovascular fitness begins to decline after one week of inactivity, with measurable increases in resting heart rate and simultaneous decreases in blood volume after that interval. Flexibility declines as well, and power (defined as strength times distance over a period of time) diminishes faster than strength. In general, the rule of thumb is that it takes three weeks of training to gain back what is lost for every one week of detraining. Which is to say, it doesn't take long to lose what you invested so much time in gaining.

Detraining and Muscle Loss:
It's Not All Bad News

Fortunately, there are mitigating factors that can help you retain muscle mass longer during times of detraining. One is simply the duration of your previous regimen of training and the level of fitness you've attained over that time. Athletes who are well-trained and have participated in a consistent regimen of physical exercise for one year or more will lose their gains more slowly than people whose training regimen is of shorter recent duration and more intermittent.

In fact, researchers have suggested that athletes who have attained a high level of fitness may retain most of that capacity for as much as three months of relative inactivity, while those newer to training can lose as much as 80 percent of their gains in as few as two weeks. When it comes to training volume, clearly consistency is key. Make the investment.


The other mitigating factor is nutrition. Or, more specifically, the branched chain amino acids leucine, isoleucine and valine. BCAAs are essential because they are the building blocks of protein. The body uses them to facilitate muscle growth and repair and yet does not produce them; they must be assimilated through food. BCAAs have long been a valued tool in the arsenal of athletes who are entering into a period of caloric deficit to cut fat while retaining muscle.Leucine, in particular, functions as the primary activator of the mTOR anabolic pathway that governs protein synthesis and consequent muscle repair and growth.

Clinical findings in the Journal of the International Society of Sports Nutrition suggest that BCAA supplementation will maintain lean mass and improved recovery even during periods of substantial caloric restriction. It stands to reason, then, that BCAA supplementation would, at the very least, help expand the window of muscle and strength retention during periods of detraining as well. During those intervals, then, it would be well-advised to supplement with either a BCAA supplement or a superior-quality protein formula or mass builder (such as ProSource's NytroWhey Ultra Elite or BioQuest's MyoZene) that has been augmented with an advanced leucine delivery system. And, of course, to keep your period of detraining to at most a week or so.

We can't emphasize enough that nutritional supplementation is no substitute for diligent, targeted training. You can mitigate the deleterious effects of detraining over the short term, but otherwise, nothing works better than hard work.


Dirks ML, Wall BT, van de Valk B, Holloway TM, Holloway GP, Chabowski A, Goossens GH, van Loon LJ. One Week of Bed Rest Leads to Substantial Muscle Atrophy and Induces Whole-Body Insulin Resistance in the Absence of Skeletal Muscle Lipid Accumulation. Diabetes. 2016 Oct;65(10):2862-75. doi: 10.2337/db15-1661. Epub 2016 Jun 29.

Vigelsø A, Gram M, Wiuff C, Andersen JL, Helge JW, Dela F. Six weeks' aerobic retraining after two weeks' immobilization restores leg lean mass and aerobic capacity but does not fully rehabilitate leg strength in young and older men. J Rehabil Med. 2015 Jun;47(6):552-60.

Delshad M, Ghanbarian A, Mehrabi Y, Sarvghadi F, Ebrahim K. Effect of Strength Training and Short-term Detraining on Muscle Mass in Women Aged Over 50 Years Old. Int J Prev Med. 2013 Dec;4(12):1386-94.


The articles featured herein are for informational purposes only and should not be construed as medical advice. Specific medical advice should only be obtained from a licensed health care professional. No liability is assumed by ProSource for any information herein.