When you don’t get enough sleep, your energy levels plummet. You become sluggish, irritable and unable to concentrate. Over time, this can lead to serious health problems like obesity and heart disease. Yet, until recently, sleep was considered a secondary concern. Even physicians often overlooked it as a major factor in people’s overall health.
Today, however, researchers are uncovering evidence that sleep is essential to the brain and body’s processes. “Sleep is one of the most active periods in the brain,” says Ze Wang, a researcher at the University of Maryland School of Medicine. “Insomnia can be associated with changes in grey matter and cognitive decline.”
Insufficient sleep may also be linked to depression, anxiety and poor job performance. It can contribute to high blood pressure, obesity and diabetes, and it may increase the risk of a stroke or heart attack. In addition, a lack of sleep has been associated with an increased risk of car accidents, and it can interfere with a person’s ability to learn.
The human body goes through four stages of sleep each night, each with a different depth of rest and characteristic patterns of brain waves. The sleep cycle begins with non-rapid eye movement (NREM) sleep, which is characterized by a slowing of the heart rate, breathing and brain activity. NREM is followed by REM sleep, in which the heart rate and blood pressure rise, and the brain shows more complex combinations of slow and fast patterns. During REM, dreams occur.
Another key function of sleep is the consolidation of memories, which happens during a non-REM stage called slow-wave sleep. During this phase, the brain starts to organize and consolidate memories from the day and from childhood. Without sufficient sleep, it’s difficult to recall details from the past and can impair our ability to make decisions and solve problems.
During sleep, the immune system works to destroy viruses and bacteria that might cause infection and help the body repair tissue damage. Studies show that sleeping well reduces the risk for some chronic diseases, including cancer and heart disease. Getting enough sleep can also improve your reaction time, mood and memory.
For most adults, the goal is to get about seven to nine hours of sleep each night. If you have trouble sleeping, try setting a regular bedtime, turning off your electronic devices at least an hour before you plan to go to sleep and practicing relaxing activities, such as meditation or reading. Having a set routine can “train” your brain to recognize when it’s time to start winding down for the night. And try to avoid caffeine and alcohol before bedtime — they can interfere with your sleep.