The Science of Sleep
Sleep is a natural process that allows the body to grow and repair itself. It’s also a critical part of memory consolidation, and helps the brain clear out protein debris that could otherwise build up and lead to damage or cell death. The Centers for Disease Control and Prevention recommend that adults get a minimum of seven hours of sleep per night. People who don’t get enough sleep are more likely to have a variety of health problems, including obesity, high blood pressure, heart disease and depression.
The science of sleep began with a UChicago professor and pioneer in the field, Nathaniel Kleitman, who created the world’s first lab solely focused on sleeping. Kleitman studied how the brain’s activity changes as you go through different stages of sleep. He and his colleagues used all-night electroencephalogram (EEG) recordings to chart these patterns.
As researchers have looked more closely at the human brain, they have learned that there are two separate and distinct kinds of sleep. One, referred to as non-rapid eye movement sleep or NREM, is broken down into three stages. The other, called rapid eye movement or REM sleep, is much more active and complex than NREM. During REM, for example, brain activity occurs in neural structures usually involved in the regulation of emotions.
In addition to the behavioral and physiological criteria mentioned above, subjective experience and verbal reports of that experience are also often used to determine when a person is asleep. The problem with this is that it can sometimes conflict with both behavioral classifications and EEG tracings, making it difficult to define when someone is really asleep or not.
There are many factors that can affect how well a person sleeps, such as his or her age, medical conditions and medications, including sedatives, antidepressants, pain relievers and alcohol. The amount of sleep a person needs can vary greatly from day to day as well.
For the average person, getting enough sleep means going to bed at a reasonable hour and turning off electronics. It also helps to follow a regular bedtime routine, such as taking a warm bath or reading before turning in for the night. Practicing these behaviors will “train” the brain to recognize that it’s time for sleep and can help you get into a healthy sleeping pattern. It’s also a good idea to avoid stimulants, such as caffeine or alcohol, near the time of your normal bedtime. Too much caffeine or alcohol can disrupt the natural sleep-wake cycle and keep you awake. If you have difficulty falling or staying asleep, talk to your doctor. He or she can test you for sleep disorders and suggest ways to improve your quality of sleep. You should also see your doctor if you have health problems such as heart disease, high blood pressure or obesity that may be related to insufficient sleep. The more you learn about sleep, the better prepared you’ll be to make healthy choices when it comes to your own personal sleep habits.