Muscle loss: the science behind it and how to prevent it

The current global pandemic has forced gyms across the world to close down until further notice. Without access to weights, unless you are fortunate enough to own your own gym equipment, many people are concerned they will lose the muscle they trained hard to build. In this article, we discuss what happens when we stop resistance training, and how to prevent muscle loss. 

Muscle loss

Muscle mass is determined by complex interactions between muscle protein synthesis (MPS), and muscle protein breakdown (MPB). MPS and MPB are constantly alternating based on whether we are in a fed or fasted state. When we are in a fed state, MPS occurs, but, when we are in a fasted state, we are in MPB, as shown in the graph below. 

The balance between MPS and MPB over time is what determines whether we build, maintain, or lose muscle mass. Think of muscle building as a bank account, with income being MPS, expenditure being MPB, and net balance being muscle. When income is greater than expenditure, we create a greater net balance. When income is less than expenditure, we are in a negative net balance, and when income equals expenditure, we maintain a net balance. The same with muscle mass, a greater net balance equals increased muscle mass, negative net balance equals decreased muscle mass and maintained net balance equals no change in muscle mass. 

So far, we’ve concluded muscle loss occurs when MPB is greater than MPS, over a longer period of time. Muscle loss may occur due to decreased MPS, increased MPB, or a combination of both.

Rate of muscle loss

The rate at which you lose muscle mass depends on your activity levels. Maximal muscle loss occurs when you are at complete best rest, although this only occurs if you are hospitalized, therefore not relevant for the large majority of us. Research shows a two-week break from resistance training resulted in no significant loss of muscle mass. Individuals continued their routine activities, such as walking, and housework, and have been resistance training for at least one year. Therefore, suggesting a short break from resistance training does not result in a loss of muscle mass, if you have previous resistance training experience. 

Not resistance training for more than 2 weeks appears to be when we start to see reductions in muscle mass. Studies have shown muscle gains can be reduced by half following eight weeks of no resistance training. Losing half your gains is not at all optimal, but there are ways you can limit the amount of muscle lost. Remember, the individuals in this study completely stopped their training.

How to prevent muscle loss

There are several ways to prevent muscle loss, including factors surrounding activity, protein, and calories. 

Activity levels

Resistance training is no doubt the best way to build and maintain muscle mass. Since most of us do not currently own weight equipment, we need to rely on other ways to maintain muscle mass. Research has shown high rep bodyweight training, reaching near to failure, is enough to maintain muscle mass in trained individuals. Therefore, exercise at home should focus on going to near failure on bodyweight exercises to aid the maintenance of muscle mass. 

Protein consumption

Protein is key to maintaining muscle mass. When muscle breaks down through exercise and fasting, protein is required to rebuild it. Since training is reduced while at home, we need to ensure we are consuming enough protein to at least maintain muscle mass. Referring back to the graph, we want to keep MPS as high as possible to minimize muscle lost. It is recommended you eat 1.6-2.2g of protein per kg, per day. During this time, it might be more favourable to focus on the higher end.

Calorie consumption

Now is not the time to begin a cut, if you want to keep your muscle mass. A recent study showed muscle growth is maximized when you are in a calorie surplus (quite obvious) therefore during training at home you should aim to eat above your maintenance calories. 

Regaining lost muscle

The current global pandemic is a stressful time for all of us. For many of us, there are bigger things to think about than our diet and exercise regimes. If diet and exercise do go out the window during this time, don’t worry about regaining your muscle lost during this period. The theory of muscle memory suggests it is easier to rebuild muscle if you have training experience. If you have trained hard in the past, it won’t take you as long to rebuild muscle once you get back into the gym. 

Conclusion 

For trained individuals it is very unlikely you will build muscle while training without weights. However, it is possible to maintain or at very least minimize muscle loss through activity and diet. Bodyweight training to near failure, eating in a calorie surplus, and consuming high amounts of protein is optimal for training at home. However, if this is not possible muscle memory theories suggest muscle can be rebuilt quickly if you have resistance training experience. Therefore, don’t worry too much about losing muscle while training at home. Focus on minimizing muscle loss during this period, until the gyms open back up.