Who Needs Sleep? PDF

Who Needs Sleep? Maybe you do. Here's what you need to know about slumber, from A to Zzzzzzz's. by Kirsten Weir Quick quiz: How much of your life will you spend sleeping? Answer: A whopping one-third. For something we spend so much time doing, we don’t often give slumber the credit-or attention-i...

Who Needs Sleep? Maybe you do. Here's what you need to know about slumber, from A to Zzzzzzz's. by Kirsten Weir Quick quiz: How much of your life will you spend sleeping? Answer: A whopping one-third. For something we spend so much time doing, we don’t often give slumber the credit-or attention-it deserves. A study by the National Sleep Foundation (NSF) found that 60 percent of middle and high school students felt tired during the day, and 15 percent had fallen asleep in school during the last year. “I’m definitely tired during the week,” says Leah Schaffer, a 17-year-old junior from Oxford, Michigan. “I nod off a lot in chemistry.” But why is sleep so important? And why are so few of us getting enough? Sleeplessness Kills When we sleep, we cycle through five well-defined stages. Between stages 1 and 4, we sink deeper and deeper into sleep. Heart rate and body temperature drop. Brain waves slow down and muscles relax completely. Then we enter the fifth stage of sleep: rapid eye movement, or REM, sleep. During this stage, our eyes dart back and forth below the eyelids, and our brain waves speed up again to the same levels as when we’re awake. Most dreaming occurs during REM sleep. People need both non-REM and REM sleep in order to get a good night's rest. During a full night of sleep, we cycle through all five sleep stages between three and five times. Scientists know that we have to sleep. Repeated experiments with lab rats have shown that rats will die from lack of sleep long before they die from lack of food. Sleep-deprived people, however, don’t drop dead, but they do suffer health problems. Humans who go days without sleep begin to have digestive troubles, such as diarrhea and stomach pain. They experience memory problems and hallucinations and can quickly become paranoid. However, scientists still aren’t certain why we need to snooze. One theory is that while we sleep, our bodies repair muscles and other tissues. Some researchers believe that sleeping and dreaming are necessary for the brain to organize and store memories. Others think we slow down at night to conserve energy. Setting your Body Clock Adults need about eight hours of sleep each night, but young people need even more. “Kids from about 10 to 18 need a little more than nine hours of sleep a night, on average,” says Dr. Mary Carskadon, a sleep researcher and member of the NSF task force on sleep and teens. Yet Carskadon has found that most teens sleep an average of seven hours a night. Busy schedules are only part of the problem. During adolescence, the body's internal clock gets pushed back so that a person doesn’t feel sleepy until later in the evening. The result? Teens want to stay up later at night and sleep later in the morning. “I tend to be tired in the morning, and toward the end of the day I wake up,” Leah says. To make matters worse, nighttime habits can also affect the body's clock. One way the body learns when to sleep is through light cues. Staying up late in a bright room or staring at a brightly lit TV or computer screen can push the internal clock back even later. Sick and Tired The short-term effects of too little sleep are obvious enough. Too little shut-eye can leave you feeling fuzzy-headed and unable to concentrate. “Almost all teenagers, as they reach puberty, become walking zombies because they are getting far too little sleep,” says Cornell University psychologist James Maas in the American Psychological Association's Monitor on Psychology. Over time, skimping on sleep can cause a sleep debt to accumulate, and that can have serious consequences. “As the sleep deficit goes on week after week, your body changes,” Carskadon adds. Sleep-deprived people have problems with learning and memory. Mood is also affected, and overtired teens can show mood problems that mimic depression. In some cases, youths may be prescribed medication for depression when, in fact, they’re just way behind on sleep. Also, the hormone cortisol, which is associated with stress, can build up in the sleep-deprived. High cortisol levels weaken the immune system, making a person more susceptible to illness. New studies are also revealing that sleep debt can mess with metabolism, the chemical processes that occur within an organism to sustain life. “If you aren’t getting enough sleep, you’re likely to eat more and also process food differently,” Carskadon reports. Those metabolic changes can lead to weight gain and related health problems, including diabetes. Unfortunately, sleep debt is hard to overcome. Sleeping in on weekends is your body's way of playing catch-up-but if you overdo it, you could be making matters worse. Carskadon suggests sleeping for an extra hour or two, but not all day. Your body will thank you for it Monday morning, she says. Still, it's important to listen to your body and give it the rest it craves. “Kids need to be happier,” says Carskadon. “I think if they had more sleep, they’d be happier.”