Dreaming, snoring, tossing and turning -- there are lots of things we do while we're sleeping, but what's actually going on while you're in the land of nod?

Research has come a long way in helping us understand that sleep is more than just a required period of inactivity for our bodies and brains. "Only in the last five to 10 years has research shown that sleep is biologically programmed into virtually every single cell of your body," Michael J. Twery, Ph.D., director of the National Center on Sleep Disorders Research (NCSDR) at the National Heart, Lung, and Blood Institute (NHLBI) tells The Huffington Post.

Sleep not only restores the body after a long day, it also seems to play a role in learning and memory, growth and development and immunity, yet researchers still don't know exactly why or how sleep works its many wonders.

We do know that these different functions seem to take place during different phases of the night, although there's no one "best" stage of sleep, Lawrence Epstein, M.D., chief medical officer of Sleep HealthCenters and co-author of "The Harvard Medical School's Guide to a Good Night's Sleep" tells The Huffington Post. "In order to get all the benefits of sleep you need to get adequate amounts of sleep."

The average adult needs seven to nine hours a night, but ideally you should sleep until you wake up naturally. "If you're waking someone up from sleep, it means they haven't slept enough," says Dr. Epstein. So, that alarm clock screaming that it's time to get going? "I think it's the best way to sleep deprive yourself," he says.

In order to better understand what sleep does for your body and brain, here's a look at what's happening as you transition from going about your day to hitting the hay.

Wakefulness
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You spend the day awake, alert and burning your body's fuel. Lots of the brain's centers are firing at once to make sense of the visual, auditory and other stimulants happening all around you, says Dr. Epstein. If you were to map out the brain's activity, you'd see "chaotic, small waves" he says. "You can think of it as 'awake brain, awake body.'"

But the body is preparing for sleep long before your head actually hits the pillow, explains Twery. The darker light of evening triggers sleep hormone melatonin to rise, and the body's temperature drops slightly. "These are all signals to the body to promote sleepiness and the transition to sleep," he says.


Flickr photo by D'Arcy Norman