What Happens To My Muscles If I Stop Exercising?

Whether dealing with an injury, getting too busy with school work, or needing a break from the gym, we aren’t always able to attend the gym as frequently as we like. This raises the question: What happens to my muscles if I stop exercising?

Many people are under the assumption that our muscles atrophy (shrink from lack of stimulation) from infrequent exercise, such as going on vacation or getting sick for a week. In a recent research article titled: Bed-rest and exercise remobilization: Concurrent adaptations in muscle glucose and protein metabolism, we are able to learn the effects of rest and muscle atrophies.

Basic Breakdown

Simply put, the study found that prolonged bed rest for three consecutive days lowers glucose (useable energy) uptake and glycogen (saved-up glucose) storage, along with a decrease in muscle volume. Although this might seem significant, implementing resistance training afterward restored the lost muscle mass. However, resistance training was unable to restore glycogen stores and glucose uptake, which may take more time to restore via more consistent training. 

Having lower glucose and glycogen means that you won’t be able to exert as much energy as normal. Therefore, it is vital to restore glucose and glycogen through the consumption of carbohydrates.

Complex Breakdown

We know now that when we don’t utilize our muscles over an extended period, we begin to see muscle atrophy and decreased strength. However, this recent study shows the effect of short-term rest of muscle markers in participants. After 3 days of bed rest (without exercise), markers of leg glucose uptake decreased by 45%, glycogen stores decreased as well and Myofibrillar protein FSR (a marker for muscle protein synthesis and growth) decreased by 43%, with leg mass decreasing by 2.5% in addition. This shows the baseline of these markers after a short-term 3-day bed rest. Following this, the participants did resistance training to see how well the muscle bounced back from this setback. After this exercise post bed rest, only the leg volume was restored. The myofibrillar protein FSR was fully restored to pre-bed rest levels, but the non-exercised leg was still 35% lower than the exercised leg. However, the leg glucose uptake did not restore to pre-bed rest levels, still being 30% reduced. Glycogen was similar as well, not fully returning to pre-bed rest levels. 

This new article shows us the effect of even a short-term cease in training and immobility and the effects of muscle markers on this. Protein synthesis decreases in this time, as well as muscle mass, but these are quickly restored to baseline after introducing exercise back into your routine. But your muscle glycogen and glucose uptake is still affected by this short-term bed rest/immobility that can also negatively affect your gains after this period. It is important to understand here the major implications that short-term bed rest has on muscle markers. To bounce back from this, continuation of exercise is the best recovery for these markers with adequate protein and carbohydrate intake.

Research article link: Bed-rest and exercise remobilization: Concurrent adaptations in muscle glucose and protein metabolism