Getting a good night’s sleep makes you feel better both mentally and physically. And, if the results of new research are to be believed, it might also help you fight some of the “diseases of civilization” that are plaguing modern life. Whether you are an athlete or a couch potato, it’s likely that you know how much better you can perform when your body and brain are well rested. But what many people don’t realize is that sleep does much more than simply reenergize the brain and body for daytime activities. In fact, it repairs the body on a cellular level and strengthens key systems that protect against diseases and injuries.
During the sleep cycle, the brain shifts from fast-paced alpha waves to slower theta waves, and the electrical signaling between neurons begins to slow down as a person drifts off into a deep sleep. These slowing brain waves are reflected in an EEG (electroencephalogram) tracing as the first signs of sleep are seen as the appearance of brief, intermittent sequences of low-voltage mixed-frequency brain activity, known as “sleep spindles.”
Other physiological changes that are reflected in the EEG tracing during this early stage of sleep include the relaxation of the skeletal muscles and the loss of overt goal-directed behavior. Although not always reliably present, these signs are generally enough to distinguish sleep from other states such as waking or hibernation. In humans and most other mammals, a horizontal posture is also usually indicative of sleep because it indicates a decreased sensitivity to the environment.
This is called NREM (non-rapid eye movement) sleep. During this phase, the heart rate slows down and the body temperature drops. The NREM cycle ends when a rousal, often signaled by the onset of snoring or a groan, occurs.
The other major type of sleep is REM (rapid eye movement) sleep, which is characterized by a burst of activity in parts of the brain normally associated with emotion. This is the state that we are most familiar with from dreams.
It’s time to rethink our attitudes toward sleep, which experts say is critical for both mental and physical health. Lack of it can increase a person’s risk for high blood pressure, diabetes and depression and lead to overeating. On the flip side, adequate amounts of sleep can reduce a person’s weight by impacting the hormones that make you hungry. And a recent study found that sufficient sleep can improve the cardiovascular system by lowering blood sugar, cholesterol and blood pressure levels while boosting immune function and strength, memory and learning abilities, and libido. These results suggest that sleep should be a top priority along with the American Heart Association’s Life’s Simple 7–which includes healthy eating, physical activity, no smoking and moderate alcohol consumption.