Sleep requirements change during the course of a lifetime most children need more sleep, most older adults, less. Still, most middle-aged people function best on seven to nine hours of sleep, while others need up to 11 hours. There is no "normal" amount of sleep what matters is how well, not how long you sleep. The two states continue to alternate, with four to six 90- to 110-minute cycles occurring during the course of a typical night's sleep. The sympathetic nervous system is active, stimulating production of adrenaline, the "stress hormone." Most men develop penile erections during REM sleep.Īfter about 30 to 45 minutes, sleep shifts back from REM to the non-REM pattern. Although the body is entirely relaxed, the heart rate and blood pressure fluctuate from low to high the heart pumps less blood to the body but more to the brain. But the brain is turned on dreaming occurs only during REM sleep. Breathing is very slow and may even pause briefly. In contrast, the limb muscles are completely limp and immobile. Although the eyes remain closed, they move rapidly in all directions. The muscles are relaxed, but body movements do occur.Īfter about 45 to 60 minutes, sleep shifts into its REM phase. The circulation slows, too, as the heart rate and blood pressure fall. During non-REM sleep, the mind slows down. They enter non-REM sleep first, moving gradually from light sleep (Stage 1) to deep sleep (Stage 4).
Good sleepers fall asleep quickly, usually in less than 15 minutes. Sleep is divided into two major phases, rapid eye movement (REM) sleep and non-rapid eye movement (non-REM) sleep. But although it's restful, sleep is actually quite complex and busy in its own right. Sleep is essential for health, providing rest and restoration for mind and body. Fortunately, lifestyle changes and behavioral treatment can help many sufferers, and medication is available for those who need it. A lucky few get relief from counting sheep, watching late-night movies, or sipping warm milk (or something stronger) - but most people with insomnia need more assistance. But for many men, it's a nightly struggle. Nearly everyone has spent at least one night lying in bed wishing for sleep.
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