The Importance of Sleep in Muscle Recovery.
Sleep, a state that occupies about one third of our lives, is as basic a need as food, and vital to physical well-being. Sleep gives us more than just rest; it recharges our “battery,” (nervous system) and replenishes our energy stores. The deeper and better we sleep, the better we recharge.
Every night when we sleep, our body is busy repairing itself from all the wear and tear we subjected it to during the day. You may think you’re getting stronger when you work out, but in actual fact, you’re getting stronger when you sleep, as this is when your levels of growth hormone increase.
Sleep has a significant impact on muscle recovery, if you don’t get enough of it, you’re not going to feel rested in the morning, and your muscles will not recover properly. In order to understand sleep’s impact on muscle recovery let's look at the two main stages of sleep.
REM (rapid eye movement) Sleep: occurs in cycles of about 90-120 minutes throughout the night, and it accounts for up to 20-25% of total sleep time in adults. REM sleep dominates the latter half of the sleep period, especially the hours before waking. REM sleep provides the energy to the brain that supports it during waking hours and is necessary for restoring the mind.
Non-REM Sleep: known as slow-wave or deep sleep, this phase is essential for muscle recovery and restoring the body. Accounting for 40% of total sleep time, during this phase your blood pressure drops and your breathing becomes deeper and slower. Your brain is resting with very little activity, so the blood supply available to your muscles increases, delivering extra amounts of oxygen and nutrients which facilitate their healing and growth. Muscles and tissues are rejuvenated during this phase of sleep.
So, now that we know that the 'Non-REM sleep cycle' or deep sleep, is the most important for muscle recovery, something else which occurs during adequate time in this phase is the secretion of growth hormone. As your body enters into the deep sleep stage, your pituitary gland releases a shot of growth hormone that stimulates tissue growth and muscle repair. Not enough sleep causes a sharp decline in growth hormone secretion. Growth hormone deficiency is associated with loss of muscle mass and reduced exercise capacity. Source: SportsLab NYC
It is clear that sleep is the most important time to recover from your day. Adequate levels of sleep help to provide mental health, hormonal balance, and muscular recovery. Everyone has individual needs based on their lifestyle, workouts, and genetic makeup, but sleeping for 7-9 hours per night is crucial, especially if you are looking to change body composition, increase muscle mass and/or if you want to be ready for your gym session the next day.
So what happens when we don't sleep well? Aside from our nervous system not fully recharging, our body’s ability to heal itself is impacted, our muscle growth and recovery starts degrading, we feel tired, unmotivated, and weak in our workouts. Poor sleep has been linked to depression, an increased risk of heart disease and stroke, and increased inflammation. A lack of sleep can affect our body weight. Two hormones in the body, leptin and ghrelin, control feelings of hunger and fullness. The levels of these hormones are affected by sleep. Sleep deprivation also causes the release of insulin, which leads to increased fat storage and a higher risk of type 2 diabetes. Add that to our inability to secrete growth hormone to build and repair the muscles we worked hard on earlier in the day and we could be left wondering why we aren't reaching the goals we'd hoped for.
If you are putting in the work at the gym, but not seeing the results, have you considered your sleep patterns? Sleep is so, so important.
Wishing you health, happiness + a good nights sleep