How Sleep Affects Muscle Recovery after a Strength Training Workout

How Sleep Affects Muscle Recovery after a Strength Training Workout

(Last Updated On: October 6, 2019)

muscle recovery

Strength training builds muscle strength and can help you build and maintain muscle mass. That’s important since you begin to lose muscle mass in your 30s. However, muscle and strength loss speeds up in women after menopause. Along with the loss of muscle comes bone loss and an increase in visceral fat, a deep abdominal fat linked with inflammation and health problems, like type 2 diabetes and cardiovascular disease. Working your muscles against resistance also lowers the risk of sarcopenia, a pathological loss of muscle tissue that’s becoming an epidemic in older, inactive women.

Train hard and be consistent! But there’s more to the muscle and strength building equation than lifting weights. You need enough protein and calories to build muscle tissue. Another component some people don’t emphasize enough is rest. We know that muscles grow when you stimulate them through training but hypertrophy occurs between training sessions when your muscles are resting. You must also support them with adequate protein and nutrition. However, muscles grow between weight-training sessions and they need sufficient time to repair before you challenge them again with heavy resistance. That’s why it’s important not to work the same muscle groups until at least 48 hours have elapsed.

What happens when you rest? Behind the scenes, muscles repair the tiny micro-tears in the muscle fibers that form when you strength train by laying down new contractile elements called myofilaments within a muscle’s myofibrils. When you lay down new myofilaments, your muscles can contract with more force. Since the new myofilaments increase the size of the myofibril, the muscle fibers, muscles also grow in size and everyone’s happy. Yet there’s another component you need for muscle growth, adequate sleep. It’s an aspect of training we can’t ignore if we want the most benefits.

Sleep and Muscle Recovery

How much do you sleep each night? If you’re like most people, not enough and it’s a mistake that can cost you gains. Not only does strength training place stress on your body, but you also need an appropriate amount of rest to optimize muscle repair and growth. During sleep, muscles aren’t actively moving, and this gives them the downtime they need to recover, repair, and grow. Remember those myofilaments that help your muscles generate new force? Muscles repair and assemble more of these proteins during sleep. In fact, research shows skimping on sleep reduces muscle protein synthesis. Therefore, it can limit gains.

Sleep isn’t a homogenous state of unconsciousness. Wakefulness varies throughout the night, which is why we divide sleep into phases. Broadly, there is a rapid-eye-movement (REM) phase of sleep and a non-rapid eye movement phase (NREM), also referred to as deep sleep. During the N3, or third, stage of NREM sleep is when most muscle tissue growth and repair takes place. It is the deepest stage of NREM sleep, and you cycle through it several times per night. During N3, you have slow brain waves called delta waves. Heart rate and metabolism slow, and your body focuses on repair including muscle repair. Therefore, it’s easy to see why you need to sleep enough. Your body needs to spend enough time in N3 for full repair and recovery to take place.

Growth Hormone, Sleep, and Muscle Recovery

It’s also during the N3 stage of NREM sleep, or deep sleep, that your brain releases the most growth hormone and it does so in short pulses each time you enter the N3 stage of sleep. During the night, you will cycle through this stage several times. The growth hormone that aids in muscle repair stimulates the growth of bone and connective tissue that supports your frame. Plus, it promotes fat breakdown. Men have ten times more testosterone than women. Therefore, they’re less dependent on growth hormone for muscle repair. In contrast, women need the boost in growth hormone that takes place during sleep as they have less of the anabolic hormone testosterone.

It’s not hard to see why sleep is so important for muscle recovery! Deep sleep is the most restorative, and it’s when the most growth hormone enters your bloodstream to help with muscle repair. If you’re skimping on sleep, you will cycle through the deep stages of sleep fewer times, leading to less growth hormone release. During the deep, restorative stage of sleep, growth hormone release goes up by 20 times above baseline. You need access to this growth hormone to optimize recovery from a tough workout.

If you deprive yourself of sleep too long or do it regularly, it can trigger a rise in cortisol, the stress hormone. While growth hormone is an anabolic hormone that helps muscles, connective tissue, and bones repair and rebuild, cortisol has the opposite effect. It sparks muscle and bone breakdown. That’s what you DON’T want when you train hard. Plus, cortisol suppresses the immune system.

Do Athletes Need More Sleep?

If adequate sleep is vital for muscle recovery and repair, do athletes and people who work out hard need more of it? Some studies show that more sleep improves athletic performance. For example, a Stanford study found that women tennis players who strived for 10 hours of sleep each night over 5 weeks boosted their sprint speeds and accuracy when playing tennis. Getting enough sleep also helps from a motivational perspective. It’s hard to stay motivated and perform your best when you’re sleep-deprived.

The Bottom Line

We focus a lot on proper strength training and nutrition, but you need adequate sleep too. Without it, you’ll spend less time in the deep stages of sleep where your muscles repair and rebuild. Plus, chronic fatigue and lack of sleep can increase the catabolic hormone cortisol.  Make sure you’re balancing training with rest and sufficient sleep. Without it, you make it harder for your muscles to grow even if you do everything else right. So, make sure you’re prioritizing sleep just as you do training and nutrition. It’s an important part of the muscle-building equation!



·        J Musculoskelet Neuronal Interact. 2009 Oct-Dec;9(4):186-97.

· “How Sleep Adds Muscle”

·        Harvard Health Publishing. “Growth hormone, athletic performance, and aging”

·        J Appl Physiol (1985). 2017 Mar 1;122(3):549-558. doi: 10.1152/japplphysiol.00599.2016. Epub 2016 Nov 17.

· “Do Athletes Need Extra Sleep?”


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