An average adult needs between 7.5 and 8 hours of sleep per night. “But many people can function with 6 hours' sleep, and there also some who need 9 hours or more,” says Sudhansu Chokroverty, MD, professor and co-chair of neurology and program director for clinical neurophysiology and sleep medicine at the New Jersey Neuroscience Institute at JFK Medical Center in Edison, N.J.
Try to go to sleep and get up at the same time every day. This helps set your body’s internal clock and optimize the quality of your sleep. Choose a bed time when you normally feel tired, so that you don’t toss and turn. If you’re getting enough sleep, you should wake up naturally without an alarm. If you need an alarm clock, you may need an earlier bedtime.
During the late '60s and early '70s, sleep studies suggested that the neurotransmitter serotonin may play a role in sleep induction. Later on, research in animals showed that destruction of parts of the brain that housed nerve cells containing serotonin could produce total insomnia. Partial damage to these areas of the brain caused variable decreases in sleep. The percentage of destruction of these particular nerve cells correlated with the amount of slow-wave sleep.