How much sleep do we need?
Most adults require seven to nine hours of sleep for optimal rest. Some texts say nine hours is the perfect amount for slowing the aging process, for recuperation from stress and for complete rejuvenation. Adequate and effective sleep is crucial to health. This is because hormones, like melatonin and growth hormone, which have beneficial effects on our body tissues, healing mechanisms and metabolism are released during sleep.
Not sleeping enough or not sleeping in complete darkness will decrease our production of melatonin, while insomnia, sleep apnea or just not making sleep a priority will result in decreased levels of growth hormone. Decreased amounts of growth hormone have also been found in individuals with poor quality sleep or insufficient amounts of deep sleep.
Along with low levels of melatonin and growth hormone, stress hormone levels—particularly cortisol—increase. Cortisol results in increased appetite despite ample food intake, typical of people with sleep deprivation.