Here's How Sleep Quality Impacts Muscle Mass

Sleep is an essential part of life. Unfortunately, during busy or stressful times it often gets sacrificed. It may not seem like a big deal to skip out on a few hours of sleep here and there in the name of productivity, however, poor sleep quality can impact a lot more than just your mood. 

Sleep deprivation can negatively affect your muscles. 

More specifically, your body’s ability to adequately repair and recover post-exercise when trying to build muscle mass and strength. Additionally, a growing sleep debt may cause your muscles to atrophy, which is the thinning or loss of valuable muscle tissue [1]. 

What Happens When You Sleep?

Sleep is your body’s opportunity to rest and restore, but what actually happens when you sleep?

Our body cycles through two different stages during sleep, REM (rapid eye movement) and Non-REM stages. Your body will cycle through these different stages many different times in the night and each cycle can last anywhere from 1-2 hours at a time.

There are 3 different types of non-REM sleep, stages 1 and 2 occur when you initially fall asleep while stage 3 occurs when your body begins to enter a deep sleep. Your body uses this time to repair your tissues and muscles. 

REM sleep is the last stage of sleep and is characterized by deep sleep and often begins around 90 minutes after you initially hit the hay. 

During these different sleep cycles, your brain waves, heart rate, and eye movements will slow down or speed up while your body releases various hormones to aid in rest and recovery [2].

What Does Sleep Have to Do With Muscle?

Because sleep is a time for your body to restore, recover, and rebuild, it is an essential part of building lean body mass. 

When we hit the gym, we want to see results. During this time, our body needs to be provided optimal conditions to replenish and repair post-exercise. Diet and strength training are essential during this process however, sleep is also a necessary component.

Not only does our body release specific hormones during sleep to help with replenishing and recovering from our workouts, but it also helps us to manage our metabolic health overall. 

What Happens if I Don't Get Enough Rest?

Your sleep is centered around your circadian rhythm, which is your body’s natural clock. Alterations in your sleep schedule or circadian rhythm can have implications on your metabolic function. 

Additionally, sleep plays an important role in hormone regulation. Hormones such as human growth hormone (HGH), melatonin, cortisol, leptin, and ghrelin are all affected by our sleep pattern. 

These different hormones are associated with things such as stress, hunger, satiety, and growth and regeneration of tissues such as muscle. 

When these hormones get out of whack, our body has a difficult time with building muscle and maintaining a healthy weight [3].

Human Growth Hormone (HGH) and Sleep

When it comes to muscle growth, HGH is an essential hormone for this process. 

HGH is released in small portions throughout sleep and functions to repair and grow muscle tissue. Not getting adequate sleep at night can reduce the amount of HGH your body produces, meaning you may want to take a second look at your sleep routine after all [4]. 

To add to it, sleep deprivation can decrease other essential hormones for muscle growth, such as testosterone and insulin-like growth factor-1. These hormonal shifts can result in a decrease in muscle protein synthesis (MPS), the process of building muscle from protein, and increase muscle breakdown.

How Does Sleep Impact Training Performance?

If you’ve ever been sleep deprived, you can probably imagine how it may impact your training performance. Sleep deprivation can impact every aspect of your life if left out of control. 

If you are chronically exhausted, you are less likely to train consistently or have the energy to train as hard as you normally would if you were well-rested. Additionally, studies have linked increased sleep quality and duration to improvements in areas such as reaction time, accuracy, and endurance performance [5].

How to Support Muscle Repair During Sleep?

The best way to support muscle repair during sleep is to make sure you are getting adequate protein throughout the day for MPS. 

The recommended daily allowance of protein for adults is 0.8 grams of protein per kilogram of body weight. However, research suggests higher protein intake can help to boost muscle growth in those who regularly train.

According to the American College of Sports Medicine, individuals should aim to consume between 1.2-1.7 grams of protein per kilogram of body weight per day (0.5-0.8 grams per pound) in combination with regular resistance training [6]. 

The best source of protein comes from animal products such as meat, fish, poultry, eggs, and dairy. You can also find good sources of protein from some plant-based products such as tofu, edamame, and tempeh.

Additionally, some studies suggest consuming a good source of protein before bed, particularly casein protein, may help boost HGH and increase MPS. This is because it provides your body with a boost in amino acids to use during this restorative time while HGH is elevated [7].

These studies have led the International Society of Sports Nutrition to recommend 30-40 grams of casein protein before bed to help boost MPS overnight, especially for athletes who train in the mornings on an empty stomach [8].

How Much Sleep is Optimal for Muscle Mass?

The Centers for Disease Control and Prevention (CDC) recommends adults get between 7 to 9 hours of restful sleep per night. To ensure optimal muscle mass, you should aim to get no less than 7 hours per night [9].

If you get less than 7 hours or you struggle with getting restful sleep, your body will begin to secrete less HGH which is associated with a decrease in muscle mass. Additionally, your muscles won’t get the chance to fully repair as they would if you were getting good sleep. This can make them more prone to injury [10]. 

Sleep is also when our body replenishes our muscle’s main source of energy, glycogen. If this is interrupted, your body struggles to store adequate glycogen over time which can impact your performance [11]. 

What if I Have Trouble Sleeping?

If you have difficulty getting to sleep at night, consider the tips below to help ditch counting sheep in lieu of extra Z’s. 

Limit Caffeine

A cup of coffee in the morning is essential for many. It helps us to get the kickstart we need to start the day. However, caffeine can impair our sleep, especially if consumed in excess. 

If you feel like caffeine may be hindering your sleep, consider cutting down to no more than 1 cup in the morning or limiting caffeine after noon. This includes any caffeinated beverage such as coffee, tea, some sodas, energy drinks, and some pre-workouts. 

Get Into a Sleep Routine

Our body thrives off of routine. Knowing what is happening next not only helps our circadian rhythm, but also makes it easier to prioritize sleep if we have a set routine. 

Plan to get to bed around the same time every night and wake up around the same time in the morning. It doesn’t always have to be exact but try on most days to keep it within an hour range to help your body get used to this routine. This will allow you to eventually fall asleep easier at a set time so that you can prioritize sleep without getting off track or distracted. 

Cut Down on Blue Light

Blue light exposure before bed, such as the light that exudes from our television, phone, tablet, and computer, can impact our circadian rhythm and make it harder to fall asleep and stay asleep. If you are struggling to fall asleep or have poor quality sleep, consider cutting out exposure to blue light sources 1-2 hours before bed. 

Although it may seem impossible to relax without the help of your tv or smartphone to wind down, there are other activities you can add to your routine that may be more beneficial, such as reading, stretching or doing yoga, meditation, taking a bath, or sipping on herbal tea.