How Lack of Quality Sleep Limits Muscle Growth


How Lack of Quality Sleep Limits Muscle Growth

Not sleeping enough? Tossing and turning when you crawl into bed? It’s frustrating and frustratingly common – and it could be impacting your muscle growth. If you lead a busy life, you might not prioritize sleep enough. Many people don’t. According to Medscape.com, the amount of sleep Americans get has declined over the last 45 years by 1.5 to 2 hours. Currently, many people are sleeping only 5 to 6 hours a night. Not surprisingly, they feel tired and lack motivation the next day.

You might think that eating a healthy diet and working out makes up for your lack of quality downtime but sleep is an integral part of the muscle-building equation as well. If you’re trying to build strength and more defined muscles, lack of quality sleep can interfere with your goals.

How Lack of Quality Sleep Interferes with Muscle Gains

You train hard, you eat well, but you’re not seeing the results you expected. Could it be your sleep habits? Absolutely! It’s during sleep that muscles and tissues repair themselves and this happens under the direction of a number of hormones. When you don’t sleep enough or you get poor quality sleep, it disrupts these key hormones and this, in turn, interferes with your body’s ability to repair itself. Remember, muscles grow as they repair the muscle fiber damage they sustained during strength training.

The Cortisol Effect

One hormone that’s strongly impacted by your sleep habits is cortisol. Think of cortisol as a catabolic hormone that helps your body get the energy it needs. For example, when you fast, overtrain, or are under high levels of stress, cortisol, the stress hormone, causes muscle protein breakdown. In turn, your liver converts the amino acids from muscle protein to glucose as an auxiliary fuel supply.

When you don’t sleep enough, the master cortisol producer, your adrenal glands, pump out MORE cortisol. This outpouring of the stress hormone sends your body into a catabolic state that cannibalizes your muscle tissue. Cortisol is your enemy if you’re trying to build muscle. It has another downside too. Longer term elevation of cortisol, due to chronically poor sleep, can lead to gains in belly fat as well.

Human Growth Hormone

In contrast to cortisol, growth hormone is an anabolic hormone that works in your favor when you’re trying to build muscle and lose body fat. You release the highest quantity of growth hormone during the deeper stages of sleep. Studies show that when you’re deprived of sleep, especially deep sleep, the release of growth hormone is suppressed. So, you don’t get the anabolic boost that you normally get when you sleep well and long enough.

Insulin & Testosterone

Lack of sleep also contributes to insulin resistance, a condition characterized by decreased cellular response to insulin. When cells don’t respond readily to insulin, they can’t take up nutrients, including amino acids, as easily. This makes it harder for muscle cells to build new muscle proteins. Plus, over time, insulin resistance increases the risk of heart disease and type 2 diabetes.

What about testosterone, the ultimate muscle-building hormone? Women produce less testosterone than men but the amount they do make helps with muscle growth. Lack of quality sleep interferes with testosterone production as well.

Summing It Up

As you can see, lack of sleep, sends your body into a catabolic state, as growth hormone and testosterone are suppressed and cortisol works overtime. Even if you’re consuming protein and training hard, lack of high-quality sleep can be the missing link between you and stronger, more defined muscles.

How Much Sleep Do You Need?

Are you sleep deprived? We’re each a little different genetically and some of us may need more sleep than others. However, based on research, between 7 and 9 hours a night, is the “sweet spot” for general health. This recommendation is based on the National Sleep Foundation’s review of 300 medical journals by 18 leading experts in the field of sleep.

It’s possible that you need more sleep than this if you’re under stress or train hard. How will you know? Experiment to see what works best for you. If you feel well rested and energetic on 7 hours of sleep, you may not need 8 hours of sleep most nights. Keep a sleep diary where you record your hours of sleep, the quality of your sleep, and how you felt the next day. However, avoid getting less than 7 hours of sleep a night.

Make It Easier to Fall Asleep

What if you have problems drifting off to sleep? If you have trouble falling asleep or staying asleep, try these sleep hacks:

·       Go to bed and get up at the same time each day, even on the weekends.

·       Drop the temperature of your sleeping area to 60 degrees F. Studies show people sleep better in a cooler environment.

·       Leave electronics out of the bedroom and don’t use them within 2 hours of sleep. Blue light from devices interferes with sleep.

·       Don’t consume caffeine after 1:00 P.M.

·       Train in the morning if exercise interferes with your ability to sleep.

·       Don’t eat a large meal before bedtime.

·       Do something relaxing before bedtime – hot bath, meditation, sip a cup of herbal tea

·       Check with your doc and make sure you don’t have a health condition that makes it harder to sleep, such as sleep apnea

·       Some medications make it harder to sleep too. Make sure you’re not taking one.

·       Don’t take medications for sleep, even over-the-counter ones. Not only are some habit forming but they also can have serious side effects.

The Bottom Line

Don’t let sleep make it harder to meet your weight training goals. Sleep is the ultimate opportunity for your muscles to recover and there’s no substitute for it. Make sure you’re getting what you need!



Med Hypotheses. 2011 Aug;77(2):220-2. doi: 10.1016/j.mehy.2011.04.017. Epub 2011 May 7.
J Psychiatry Neurosci. 1991 Jul; 16(2): 96–102.
Medscape. “The Impact of Sleep Deprivation on Hormones and Metabolism” January 30, 2017.
National Sleep Foundation. “How Much Do We Really Need?”
Sleep. 1997 Oct;20(10):865-70.
Diabetes Self-Management. “Sleep Well to Avoid Insulin Resistance, Study Suggests”
Science Daily. “Sleep loss dramatically lowers testosterone in healthy young men”


Related Articles By Cathe:

Does Lack Of Sleep Increase the Risk of Training Injuries?

5 Reasons When You Try To Build Muscle Your Gains Are Slower Than You’d Like

5 Hormones and How They Affect Your Body Composition


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