Sleep, Muscle Growth, and Recovery

Introduction

Building muscle has many well-researched benefits. Lean muscle helps with weight management, increasing bone density, decreasing the risk of chronic disease, and improving the overall quality of life. 

Exercise for muscle growth takes on a significant role as we get older, but did you know that muscle grows while at rest? And when it comes to rest, there is no better approach than sleep.  

As any bodybuilder or fitness enthusiast would tell you, muscle and sleep have a deeply intertwined relationship.

Most fitness fanatics are curious about the exercise-sleep dynamic. Awareness of how these components work separately and together will go a long way for insight into optimal health.

Exercise and Sleep

At its most basic level, exercising burns up energy and causes temporary fatigue, which, in turn, allows for better sleep. 

Consequently, better rest in the form of sleep allows for more energy to perform more physical challenges, like formal exercise. 

Moderate levels of exercise are the most beneficial for improving sleep quality.

The Center for Disease Control (CDC) defines moderate exercise as raising the heart rate and breaking a sweat. 

Healthy adults should get a minimum of 150 minutes of moderate exercise per week, including aerobic activity, such as jogging or walking at a fast clip, and exercises that stimulate muscle growth, such as lifting weights.

The keyword here is moderate, as studies on elite athletes[1] and overactive children[2] have found that extreme levels of exercise have the opposite effect and can interfere with a good night’s rest. 

The type of rest that is uniquely acquired through sleep is crucial for recharging energy levels. Within this type of deep rest, the body undergoes positive changes that build lean tissue-like muscle. 

Sleep, Muscle Recovery & Growth

There is an excellent reason why personal trainers and other fitness professionals regularly stress the importance of rest as a vital part of overall fitness.  

Rest allows the body to adapt to exercise and improve exercise performance. It replenishes glycogen (the body’s fuel for workouts and daily tasks), helps in strength development, reduces fatigue, and prevents overuse injuries.

When it comes to building muscle, the type of rest you get is of equal importance.  

Merely abstaining from physical activity helps, but the ‘total rest’ that truly drives growth can only be attained by restorative and consistent sleep. 

The results of multiple scientific studies over many years show that there isn’t a single major organ in the body or process in the brain that’s not enhanced by quality sleep, and the muscles are no exception.

Sleep & Muscle Repair

During sleep, relaxed muscles enable an increase of blood flow through the body, enabling more oxygen and nutrients to be delivered to the muscles.  

Additionally, the lactic acid that gives the feeling of soreness after a workout gets eliminated only during this type of break from activity.

Human Growth Hormone (HGH) and prolactin are two essential hormones that attain peak secretion in the body during sleep. 

While HGH repairs and rebuilds tissues, like muscle and collagen, prolactin helps control inflammation and joint recovery, making these two the superstars of building lean tissue and enabling further muscle development by strengthening joints. You will get these results nowhere else naturally but from sleep. 

Insufficient Sleep & Muscle Development

Muscle catabolism is the body’s process of breaking down muscle as a response to stress or the inability to mitigate it.[3] Loss of sleep is a potent catabolic stressor. 

Short-term and longer-term sleep problems have a catabolic effect on skeletal muscle,[4] making a good night’s sleep essential.

Insufficient sleep can cause further concerns that impact lean tissue development:

• Increased risk of injury by decreasing balance and postural control – this can lead to poor technique when lifting weights and can lead to injury
• Compromised immunity, leading to colds or flu 
• Increase cortisol production (the stress hormone) which reduces the body’s testosterone levels that are crucial to muscle growth
• Decrease of HGH
  
  

The Sleep-Exercise Relationship

The most fundamental way to get enough sleep is to get 7-9 hours of continuous shuteye on a consistent schedule.  

Healthy sleep hygiene is imperative, especially if you have occasional trouble falling or staying asleep.  

Unfortunately, this can be easier said than done if you have a sleep disorder. 

If you find yourself unable to fall asleep or have trouble staying asleep, you may wish to consult with your doctor. If they suspect a sleep disorder, they may order tests for further investigation. 

A good idea for exercisers is to keep a training log as it can help track how the body feels after certain types of exercises or workout days.  

Keeping this log will allow for easier identification of any potential issues that may impact sleep. It can further help in determining recovery needs and any workout program modification.

Finally, exercise should be done no less than three hours before bedtime whenever possible. 

The body needs some relaxation time that allows for an ‘easing in’ to bedtime.

Conclusion

We know that exercise is vital when it comes to multiple health markers. The list is practically endless, with the cardiovascular, immune system, digestion, endocrine, and other major systems positively affected.  

Building lean tissue (muscle) is a significant component of optimal health, but poor sleep can derail even the most dedicated efforts to do so.  

Practicing good sleep hygiene and understanding the interconnected relationship between muscle growth and sleep goes a long way in helping to live a longer, healthier life.  

References:

1. Halson S. L. (2014). Sleep in elite athletes and nutritional interventions to enhance sleep. Sports medicine (Auckland, N.Z.), 44 Suppl 1(Suppl 1), S13–S23. https://doi.org/10.1007/s40279-014-0147-0
2. Williams, S. M., Farmer, V. L., Taylor, B. J., & Taylor, R. W. (2014). Do more active children sleep more? A repeated cross-sectional analysis using accelerometry. PloS one, 9(4), e93117. https://doi.org/10.1371/journal.pone.0093117
3. Wolfe R. R. (2005). Regulation of skeletal muscle protein metabolism in catabolic states. Current opinion in clinical nutrition and metabolic care, 8(1), 61–65. https://doi.org/10.1097/00075197-200501000-00009
4. Lamon, S., Morabito, A., Arentson-Lantz, E., Knowles, O., Vincent, G. E., Condo, D., Alexander, S. E., Garnham, A., Paddon-Jones, D., & Aisbett, B. (2021). The effect of acute sleep deprivation on skeletal muscle protein synthesis and the hormonal environment. Physiological reports, 9(1), e14660. https://doi.org/10.14814/phy2.14660