New research that links quality sleep to good health and longevity has never been more convincing. Scientists are finding that short changing a good night’s sleep can compromise nearly every major body system, from the brain to the heart to the immune system. Folks who are unable or unwilling to sleep enough are doing one of the unhealthiest things one can do.
“I used to suggest that sleep is the third pillar of good health, along with diet and exercise,” says Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, “But I don’t agree with that anymore. Sleep is the single most effective think you can do to reset your brain and body for health.”
In spite of research demonstrating the benefits of sleep, Americans are sleeping about two hours less than they did a century ago. One third of U.S. adults sleep less than the recommended seven hours daily, and 40% report feeling drowsy during the day. The problem begins early with only 15% to 30% of U.S. teens get the 8 ½ hours a night recommended for teens.
We spend about one third of our lives sleeping but scientists did not understand what happens to the brain while we sleep until 2014. Dr. Maiken Nedergaard at the University of Rochester found that while the body appears to rest during sleep, a whole lot is happening inside the brain. Neurons pulse with electrical signals that wash over the brain in a rhythmic flow. The brain runs checks on itself to ensure that the balance of hormones, enzymes and proteins are balanced. At the same time, the brain cells contract, opening up the spaces between them so that fluid can wash out toxins.
“It’s like a dishwasher that keeps flushing through to wash the dirt away,” Nedergaard says.
Without the nightly brain wash, dangerous toxins can damage cells and interfere with their functioning. In the short term, that can affect memory and how we regulate thoughts and emotions. In the long term, lack of sleep can lead to faster aging of brain cells contributing to diseases like Alzheimer’s and dementia.
“Sleep is not just a passive state but a fairly active state on the molecular level,” says Dr. Allan Pack, director of the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania. “At night, a switch turns on so the sleeping brain can take advantage of the metabolic downtime to do some cleaning up.”
These new insights into sleep are also affecting how we look at mental health. Scientists have long known that sleep is important for memory. But it also appears to play an important role in regulating emotions and feelings. During deep dream sleep, the brain doesn’t just revisit the events of a day in a more organized way. Rather it processes the emotions attached to these recollections. When a memory is filed away during sleep, it’s also stripped of some of the powerful feelings—like fear, grief, anger or joy that may be attached to the experiences. Mental health professionals refer to sleep as “overnight therapy.”
This type of processing takes time and it happens only during deep, quality sleep over a consistent period. People who cut their sleep short or experience interrupted sleep may not be able to separate their emotional baggage from their memories. The brain tries to store the memory in a neutral way, but without deep sleep, there just isn’t enough time for that triage.
So how much sleep is enough for you? Experts recommend 7 ½ to 9 hours per night. The key is to be consistent. It is not healthy, for example, to skimp on sleep during the week with the idea that you will “make it up” on the weekends.
Make sleep an important priority in your life. You physical and mental health depends on it.