Sleep is an active physiological process, one in which your body is busy carrying out vital activities, while you are unconscious. While asleep your body alternates between two forms of sleep: rapid eye movement, or REM, and non-REM sleep. This cycle repeats several times throughout the night. While REM sleep provides the energy to the brain that supports it during waking hours and is necessary for restoring the mind, stages 3 and 4 of non-REM sleep, known as slow-wave or deep sleep, are essential for restoring the body. Even their names, slow-wave versus rapid eye movement, are indicative of their different healing natures.
Identification of Changes While Asleep
During the physically restorative phases of non-REM deep sleep, 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 and new cells are regenerated during this phase of sleep.
Benefits of Sleep and Growth Hormone
As your body enters into the non-REM deep sleep stage, your pituitary gland releases a shot of growth hormone that stimulates tissue growth and muscle repair. Lack of sleep and changes in sleep quality cause a sharp decline in growth hormone secretion. Growth hormone deficiency is associated with increased obesity, loss of muscle mass and reduced exercise capacity.
Types of Muscular Recovery
Your muscles require additional sleep and recovery time after illness, injury and surgery. This means if you are rehabbing an injury or are in postoperative physical therapy, you should consider that your body needs an extra amount of sleep to heal. In addition, muscular recovery is required after intense exercise, particularly strength and endurance training, in which the muscles have been torn down to some degree.
Time Frame for Adequate Sleep
You are considered to be sleep deprived if you sleep four hours or less per night, while eight hours constitutes normal sleep. The National Sleep Foundation's sleep guidelines recommend seven to nine hours for the average adult. One night of missed sleep will probably do little harm, but the cumulative effect of poor sleep will have a negative impact on your muscles.
Warnings About Age-Related Sleep Problems
Age-related declines in sleep quality, and decreases in the total duration of sleep over the years, particularly the amount of time spent in non-REM deep sleep, contribute to the wear and tear on your muscles and speed up the aging process. Consult your health-care provider if you have trouble falling asleep or staying asleep on a consistent basis. Your muscles need sleep as much as they need food, blood and oxygen.