The Impact of Sleep on Exercise and Muscle Growth

Believe it or not, sleep may be the exact reason why others seem to progress much faster than you are.

Or why you just aren’t seeing the results you were hoping for despite putting in the work.

The Study

The findings of a 2010 study by the American College of Physicians for example helps put this into perspective.

Researchers split subjects into two groups:

One that slept 8.5 hours per night (which is within the range of what most experts recommend)
Another group that slept only 5.5 hours per night.
Both groups were then put on a regulated calorie deficit for two weeks

The Result

Well, as expected, both groups lost the same amount of weight given that their calorie deficit was equated for. But what’s interesting is when you look at the composition of the weight they lost… the sleep deprived group lost 60% more muscle mass and 55% less fat than the group that got adequate sleep.

Therefore indicating that sleep seems to have a powerful effect on not only muscle recovery, growth, and retention but also fat loss. Now although the researchers didn’t test why exactly this was the case, other research does provide some insight.

Sleep helps prevents muscle breakdown and promotes fat loss.
Sleep impacts your testosterone levels.
Sleep affects your workout performance.

So the biggest advice we can give is make sure you get enough sleep.

Do we Need 7 or 8 Hours of Sleep?

Most adults require 7-8 hours of sleep for optimal health and cognitive function. Sleep needs can vary, so it’s essential to listen to your body’s signals and prioritize consistent, quality sleep to support overall well-being.

To put it simply – if you don’t get enough sleep, or get too much sleep, you may feel negative effects, so it’s worth experimenting and seeing what works for you.

How Much Sleep do you Need by Age?

Sleep needs vary by age. Newborns and infants typically need 14-17 hours, toddlers 11-14 hours, school-age children 9-11 hours, teenagers 8-10 hours, and adults (18-64) generally require 7-9 hours. However, individual variations exist, so paying attention to your body’s signals and ensuring restful sleep is crucial for maintaining good health across all age groups.

How Much Sleep is Too Much?

Of course, sleep needs vary by person to person – but as previously mentioned, 7-9 hours is the average healthy sleep amount for adults between the ages of 18 to 64. If you are frequently sleeping over 10 hours a night, make sure to speak to a health professional as this could be a sign of an underlying issue.

Do Naps Help Muscle Recovery?

Yes, naps can aid muscle recovery. Short daytime naps of around 20-30 minutes can enhance physical and cognitive recovery due to the release of hormones during sleep. Naps can help reduce muscle fatigue, support overall rejuvenation, and improve alertness, benefiting muscle repair and growth after exercise.

Does Lack of Sleep Cause Muscle Loss?

Yes, lack of sleep can contribute to muscle loss. However, don’t panic – one night of little to no sleep shouldn’t affect your gains too much (studies show that a night of poor sleep can lower muscle protein synthesis by 18%) , but it shouldn’t be a frequent occurrence.

Is it OK to Exercise on Little Sleep?

We’ve all been there – whether it’s a baby that can’t sleep, work stress, or something that’s on your mind, a poor night’s sleep can have an impact on your day – including your exercise. Exercising on little sleep can have mixed effects on your workout performance and overall health. While there’s no one-size-fits-all answer, research suggests that inadequate sleep negatively impacts athletic performance, recovery, and muscle growth.

So maybe skip the gym the day after a poor night’s sleep and focus on getting a better night’s sleep so you can work out more effectively the following day.