How Long Will It Take to Lose Muscle?

Hey Angels and Alphas,

Whether we like it or not, many of us will sooner or later have to pause our workout routines. We might be stressed at work, on a vacation, or just needing a break – there are plenty of reasons why sometimes, we’re going to take time off the gym, and that’s completely okay.

However, no matter how badly we need a break, you’re always going to worry about losing all your hard-earned muscle gains before you’re ready to start training again.

That’s why today, we’re here to break down the science of how long it takes to start losing muscle mass, and what you can do to make sure that doesn’t happen even while you’re on a break.

Let’s get right into it.

In the first 72 hours after your last workout…

If you’re someone who doesn’t particularly train or follow a regime, you’re going to see quick losses in muscle mass in the first 72 hours after your last training. Even your heart, which is a muscle as well, will show signs of decreased performance by lowering the amount of blood it can pump per beat after 72 hours off from exercise.

You’ll instantly notice the effects of stopping exercise on your heart health – much sooner than you will in your biceps or quads. If you work out on a Monday and then proceed to miss three training days (therefore training again on Friday,) you will feel a lot more breathless than usual. This is because less oxygenated blood is being sent out from the heart on every beat. Even though it’s not going to break your training, it’s actually pretty noticeable of a difference.

Although you actually start losing muscle mass after 3 days, you probably won’t notice any of the losses until you’ve gone at least 3 weeks without training. One recent study found that men who train regularly can take up to three weeks off from exercise without any noticeable loss in muscle mass.

What factors come into play when determining how fast we lose muscle mass?

How long you’ve been training (and how consistently.)

The more time you’ve spent in the gym and the more time you’ve spent on developing your muscle mass, the better off you’ll be and the longer the break you can take without experiencing any major losses. If you’re already fit, and your muscles are developed, you will have a baseline of muscle that other, less experienced lifters, will not have.

Your dietary choices and habits.

For example, adequate protein is a necessity when building and maintaining muscle mass. If you’re skipping on your protein or not getting enough, your body will simply not have the necessary amino acids (which are the building blocks of your body’s proteins) to keep up with the continuous breakdown and reshaping of cells. Eventually, your body starts pulling protein from your muscle stores in order to get the necessary amino acids it needs. The result? You guessed it, losing muscle.

One study examined sedentary and moderately active elderly women who followed a low-protein diet (which was about 1.5 grams of protein per kilogram of bodyweight every day) lost approximately 14% of their muscle mass in just 9 weeks! What’s surprising is that 1.5 grams of protein a day falls within the healthy recommended range of protein per kilogram for most older adults.

That’s why even if you’re not training, you have to make sure you’re getting enough protein to maintain healthy muscle mass.

And sure, protein needs may vary from one person to another, but as a general guideline, the INSS (International Society of Sports Nutrition) suggests that active people should aim for a protein intake between 1.5-2 grams per kilogram of body weight (and older adults should aim for the higher end of the spectrum.) To put that in perspective, that’s about 100-130 grams of protein every day for active adults.

Your age and current fitness.

There are many age-related changes that will ultimately make it harder for you to build and maintain muscle. One of them is a change related to the nervous system. 

As we’re aging, we being to lose motor neurons. Some studies suggest that there’s a drastic decrease in these motor neurons between the ages of 60 and 70. Motor neurons transmit basic impulses from the spinal cord that tell our muscles when they should contract. 

When you lose these motor neurons, it becomes very difficult to recruit more muscle fibers. And when you can’t recruit muscle fibers, this means fibers won’t break down and rebuild back stronger. 

Strength training will, however, reverse these changes to the nervous system – as well as various other age-related body changes – but that being said, once you stop training, the benefits gradually dissipate. 

Your gender.

When it comes to muscle, men tend to have a slight advantage. Men have more natural testosterone, which is anabolic to the muscle tissues and helps with their development and maintenance. (Anabolic meaning the process of building larger molecules out of smaller molecules, just like building protein out of amino acids.)

The bottom line is…

That how quickly you’ll lose your muscle mass after you stop training depends on a variety of factors, but as a general rule of thumb, you can expect noticeable losses in muscle mass in 2-4 weeks after you stop training.

If you have to stop exercising for whatever reason, and you wish to maintain and keep your hard-earned muscle mass, you could achieve a lot of luck just by doing two strength training workouts per week, as experts suggest. Target every major muscle group, do that 1-2 sets of 8-12 reps, and maintain a high intake of protein, and you’ll slow down the process of gradual size and strength loss. 

But even if you can’t, or you just don’t want to train for a few weeks, you don’t have to go back to square one when you restart your routine. As long as you’ve been training consistently up until your break, you will be able to rebuild your size and strength rather quickly.