Truly getting in shape takes more than just working out. As everyone who has ever desired a more fit physique has discovered, it often requires an entire change in lifestyle. This includes not just hitting the gym, but eating healthy and…getting more sleep?

Indeed, many people, both bodybuilders and amateurs, have noted that getting enough sleep seems to assist in putting on muscle. Several new studies back up this popular belief, offering evidence-based ways that sleep builds muscle strength and size.

How Sleep Builds Muscle

Human growth hormone is a biochemical that is essential in muscle growth. This hormone is secreted when we sleep, particularly in a phase of sleep called non-REM deep sleep. During this phase of sleep, our bodies go into repair mode. Our brains secrete muscle-building hormones while our cardiovascular system increases blood flow to the muscles. This allows our bodies to recover from the stresses of the day, but also encourages them to increase bulk and strength.

Human growth hormone also has other muscle-enhancing effects. It enhances your muscles’ ability to absorb amino acids from your bloodstream. This is essential to getting the most out of a healthy diet, particularly if you are taking supplements to increase your muscle gains.

In addition, there is a hormonal cost of not getting enough sleep. Insomnia leads to higher levels of cortisol, a hormone that can actually prevent muscle growth. Cortisol is a “fight or flight” hormone that is the biochemical enemy of fitness, inhibiting muscle growth while encouraging the accumulation of belly fat. Getting the sleep you need will ensure that your muscle cells, rather than stubborn and unattractive fat cells, are growing.

Trimming Appetites, Trimming Fat

Most people who are trying to build muscle are going for a lean appearance. Keeping a low body fat percentage is essential to getting the lean and cut look you want. After all, no one will see your muscles if they are buried under extra pounds. However, you should not give in to the temptation to cut into sleep hours to get in more time at the gym.

Going without sleep also increases levels of the hormones ghrelin and insulin. Ghrelin, also known as the hunger hormone, makes us hungrier and encourages over-eating. At the same time, high levels of insulin can make you crave sugar and other simple carbs. These two hormones can make it difficult to stick to a healthy diet crucial to becoming more fit.

In addition, sleep is crucial to burning fat. People who get less than six hours of sleep a day are at higher risk of metabolic imbalances such as insulin resistance. Metabolic imbalances will not only result in a higher percentage of body fat but a higher chance of developing serious medical conditions such as type 2 diabetes.

Keeping Your Mental Game Strong

Although lifting weights is important to building muscle, keeping mentally strong can be crucial as well. Being well-rested helps you to perform better in the gym.

Several studies have found a solid link between sleep and mental sharpness. Sleep helps us to think more clearly and to perform better on cognitive tests. Lack of sleep, on the other hand, can cause us to become unmotivated and unfocused.

Sleep also contributes to how well we perform physical tasks. People who get more sleep perform better in athletic activities. In fact, a recent study found that basketball players can increase their performance by just spending a little extra time in slumber.

Part of the mental advantage of sleep may be its role in increasing levels of the hormone testosterone. Testosterone is associated with muscle growth, but also with mental sharpness and quick reflexes. Testosterone is secreted in high amounts during REM sleep, which prepares both our muscles and our brains for the day ahead.

How Much Sleep Do You Need?

Although there is no magic amount of sleep that is right for everyone, most people need between seven and nine hours a day. This amount of sleep will help you to feel more energetic and to maintain the hormonal balance that you need for building muscle.

People who are actively working out may need to get even more sleep to aid in muscle recovery. This can be a challenge because both strength training and aerobic exercise generally leave people feeling “pumped up” and more energetic. However, this effect usually dissipates within a few hours. Research has found that people who work out more, whether it be weight training or going for a simple run, sleep better at night.

Getting enough sleep will help you to build more muscle while working out will help you to sleep. Sounds like a win-win for both your appearance and your long-term health.