It's easy to take sleep for granted, until you become sleep deprived. Whether because of a plane trip across time zones (see my "Time Travel 101" blog post) or a big test or a new baby, not getting enough sleep on a regular basis can become a health issue. In fact, sleep can do so many good things, think of it as your health care partner.
It May Affect Your Weight
Sleep can be a factor in weight problems. A National Health and Nutrition Examination Survey (sponsored by the Centers for Disease Control and Prevention) followed 8,000 adults over several years and found that subjects who slept less than seven hours a night had a greater risk of weight gain and obesity, with risk increasing for every hour of sleep lost. In another study, when caloric intake was measured over two 48-hour periods in which participants slept eight and four hours respectively, after the four-hour sleep, subjects consumed at least 500 calories more. Yet another study showed that subjects ate significantly more calories from snacks and carbohydrates after five and a half hours of sleep versus after eight and a half hours. The theory is that decreased sleep initiates a rise in ghrelin (a hormone that stimulates appetite) and a reduction in leptin (a hormone that tells the body it's full). Any weight loss program should include diet, exercise and a good night's sleep.
It Supports Learning
The all-nighter as a staple of higher learning is a myth. In fact, being sleep deprived actually impairs memory, not to mention judgment, which isn't advisable if you're guessing on multiple-choice questions (or driving a car). During sleep, the brain processes events and experiences from the day, making and strengthening connections between nerve cells (brain plasticity). This process helps reinforce the understanding of tasks and content, and strengthens the ability to comprehend and remember experiences. Fortifying the connections is why sleep is so important for effective study. If you've left all the reading material to the last minute, that's another problem, but instead of staying up all night, it's better to read and/or review your material until drowsiness sets in, and then sleep.
It Helps Emotional and Developmental Health
Because sleep helps the brain organize memories, understand experiences and integrate information it acquired during the day but didn't have time to process, sleep, or the lack of it, has a tremendous impact on a person's ability to cope. This is especially relevant to the sleep requirements of children and their emotional development. A Northwestern University study of 500 preschoolers found that of children who slept less than 10 hours in a 24-hour period, 25 percent were more likely to misbehave, and were at greater risk for acting out behavioral problems. Those who experienced sleep disturbances seemed to be prone to medical issues that included allergies, ear infections and hearing problems, as well as psychiatric and social problems like aggression, anxiety and depression. In fact, sleep abnormalities are usually present in several brain disorders like depression, schizophrenia, Alzheimer's disease and stroke.
It Moves in Cycles and Stages
Sleep is a very dynamic process that works in cycles, shifting back and forth between deep, restorative sleep and lighter stages of sleep in which you're more alert and dreaming. There are two main stages of sleep: Rapid Eye Movement (REM) sleep, which is the lightest, most active stage in which dreaming occurs. The second is deep sleep (Non-REM), which is further divided into three lighter "weights" of sleep. Deep sleep, which immediately after falling asleep, is the longest stage and produces the most restorative sleep. As the night progresses, the cycles move from deep sleep to the lighter stages, ending with REM sleep. The strongest negative effects from being sleep deprived are from inadequate deep sleep. If you want to improve your REM sleep, which may improve overall mood, try to sleep an extra half hour in the morning.
It's Very Personal
Sleep requirements are as individual as snowflakes, but a general rule of thumb is: Infants need 16 hours of sleep; babies and toddlers need 10-14 hours; children age 3-6 need 10-12 hours; kids age 6-9 need 10 hours; kids age 9-12 need 9 hours; teenagers need about 9 hours; and adults should aim for 7-8 hours. As a physician who specializes in sleep disorders once told me: "Sleep is a non-negotiable item." You need to sleep as much as your own personal physiologic makeup dictates.
It Wants to Help
If you help your sleep, it can help you. To maximize your deep sleep, try to be consistent about your sleep and wake times. It's also important to make your sleeping environment as comfortable as possible by keeping the room dark and the noise low. And no scary movies before bedtime.