Muscles are made out of long, contracting fibers wrapped into large sheaths. Building muscle, also known as hypertrophy, demands that these fibers be stressed by exercise, followed by long periods of rest. Sleep can consume up to a third of our lifetimes, and the unconscious hours provide a state in which the muscles can progressively heal and grow.
During a workout, the muscles accumulate microscopic cellular damage. The two factors that expedite convalescence of the muscles are proper nutrition and rest. The most important form of rest is sleep, which is essentially just a heightened anabolic state, meaning a time during which larger molecules and tissue are constructed. It is complicit in the rejuvenation of the immune, nervous and muscular systems, because protein metabolism occurs at a more proficient rate. You should aim for eight to 10 hours of sleep total.
Sleep gives muscles the time and impetus necessary for proper recovery. Human growth hormones and melatonin, both of which play a role in tissue recovery and immunity, are heavily synthesized during sleep. Human growth hormone stimulates growth, cell reproduction and regeneration. Its biggest spike is right after you fall asleep.
While the body seeks to achieve an anabolic state during rest, muscle hypertrophy is still a matter of a simple formula. The rate of muscle protein synthesis must exceed the rate of total muscle protein breakdown. During the post-absorptive period, which is the period when nutrients have been absorbed into the blood, the body begins metabolizing nutrients and building the muscles. Sleep is the longest post-absorptive period. By the time you wake up, most of the nutrients will probably be depleted, and the breakdown of muscle protein will have exceeded the rate of synthesis.
Amino Acid Levels
In order to inhibit protein breakdown, you need only a small increase in blood amino acid levels of about 25 to 50 percent above fasting baseline. The small increases, however, must last at least four or five hours, which most foods cannot achieve. Milk is a good panacea for this problem. It contains two proteins: whey and casein. Whey elevates blood amino acid levels to 300 percent after an hour; at the four-hour mark the levels return to baseline. Casein is more slow-acting. After four hours, blood amino acid levels are still elevated by 35 percent. Combined, the consumption of milk can keep blood amino acid levels elevated beyond the eight-hour mark. (I’ve recommended cottage cheese before bedtime for this reason.)
Cortisol is a catabolic hormone that works in the opposite fashion of testosterone. It helps cause the breakdown of muscle tissue. Stress associated with sleep deprivation or sleep disorders can cause a rise in the production of cortisol in the adrenal glands. Proper sleep, on the other hand, can relieve stress and lower cortisol to sustainable levels.
Read more: http://www.livestrong.com/article/325791-how-important-is-getting-enough-sleep-for-building-muscle/#ixzz17LrWE0n9