Sleep is an integral part of our physiology as a species since it mediates an array of functions, including structural (e.g., muscle growth, protein synthesis) and biochemical (e.g., hormonal regulation, metabolism) processes.
Unfortunately, many people neglect the power of sleeping for sufficient hours during the night and its effects on improving the performance of their organs.
One especially underestimated field is the effect of sleep on muscle growth and post-exertional recovery.
In this article, we will cover all you need to know about the relationship between sleep and muscle hypertrophy, as well as how to improve sleep hygiene.
Why is sleep important for muscle growth?
As you may know, glucose is the primary compound that’s used to produce energy in your cells.
Once glucose enters the cell with the help of insulin, it will be incorporated into numerous metabolic cascades to generate Adenosine Tri-Phosphate (ATP).
When you’re sleeping, the process of transforming excess glucose into glycogen begins, which is then stored in your muscle and liver tissues.
This helps the myocytes (i.e., muscle cells) to engage in the contraction-relaxation cycles more efficiently since glucose –in the form of glycogen– is already present inside the fibers.
If you are sleep deprived, this entire process gets disrupted, leading to slow glycogen replenishment, and consequently, poor performance and muscle growth.
To understand the specifics of how sleep influences muscle growth, we need to decipher the mechanisms first.
In a typical strength training routine, the workout is broken down into a group of exercises that you need to perform for an X number of sets.
Each set ranges between 10-15 repetitions, which refer to the number of times you’ll repeat the movement.
Let’s say you are in the gym working on your upper body.
Your workout plan consists of 4 exercises: bicep curls, dumbbell pullover, bench press, regular pushups.
You need to perform each exercise 12 times (the number of repetitions) for a total of 3 sets.
This means that by the end of your workout, you’ll have done 12 repetitions multiplied by 3 sets multiplied by 4 exercises, which gives us a final result of 144 total movements.
The reason that we’re emphasizing this point is due to a concept known as training to failure, which entails that you do as many repetitions until you can no longer move your muscles.
When you reach this point, the muscle fibers will be torn (microscopically), requiring your body to repair the damage with the help of growth hormones and proinflammatory compounds.
One major hormone that mediates this process is known as human growth hormone or HGH.
According to research, the secretion of HGH is controlled by the circadian rhythm, where most of it will be released into the bloodstream during sleep.
If you are dealing with insomnia or other forms of sleep disorders, the levels of HGH will be low, which severely impacts muscle hypertrophy.
In a 2017 cross-sectional study, researchers analyzed hundreds of clinical data to examine the relationship between the duration and quality of sleep with muscle growth in University students.
The study found a clear connection between students who slept for less than 6 hours a day and poor muscle growth.
According to another study, researchers hypothesis that “sleep debt decreases the activity of protein synthesis pathways and increases the activity of degradation pathways, favoring the loss of muscle mass and thus hindering muscle recovery after damage induced by exercise, injuries and certain conditions associated with muscle atrophy, such as sarcopenia and cachexia.”
Sleep and weight loss
Aside from the direct influence of sleep on muscle growth, it will also promote weight loss, which is a major trigger for muscle hypertrophy.
Multiple research papers and clinical studies unveiled a link between poor sleep quality and obesity.
In a 2008 meta-analysis, researchers demonstrated that sleep-deprived individuals have a higher risk to become overweight.
The review also noticed that 55% of adults and 89% of children who sleep fewer hours have a higher body mass index (BMI).
Additionally, insomniac patients reported eating more meals per day due to increased appetite. Scientists explained this phenomenon by the effect of sleep on the regulation of hunger-suppressing hormones (e.g., ghrelin, leptin).
How to improve sleep hygiene
Avoid using your phone or laptop
Digital devices are a powerful source of UV light, which suppresses the release of melatonin, and eventually, disrupts your circadian rhythm.
According to the National Sleep Foundation, people need to avoid using their digital devices 2-3 hours before bed.
Avoid exercise before your bedtime
While exercise is especially beneficial at improving sleep quality, it might interfere with your circadian rhythm by keeping your body on high alert.
This is the result of high serum levels of epinephrine, epinephrine, and cortisol which keep you on your toes and prevent sleep.
Limit the intake of stimulants (e.g., caffeine, nicotine)
The vast majority of people are aware of the effects of coffee, tea, and other caffeinated beverages when consumed near bedtime. However, the chemical composition of these substances allows them to be active even after hours of drinking your beverage.
For instance, if you drink a cup of coffee at 5 PM, your blood will still have sufficient quantities of caffeine to keep you awake.
Limit naps to 30 minutes
Napping has become an integral part of our culture that people started to ignore the appropriate duration for naps.
You see, sleeping for long hours during the day will advance your biological clock, tricking the brain into believing that you don’t need sleep at night. Consequently, transitional insomnia sets in, further messing up your circadian rhythm.
Therefore, you must limit your naps to 20-30 minutes a day.
Sleeping for sufficient hours is crucial for muscle growth and recovery, which is why you need to pay more attention to your sleeping habits.