Sleep is a defender of our brains and bodies — a pillar of health, together with diet and exercise. The Sleep Research Society, American Academy of Sleep Medicine, and the National Sleep Foundation all recommend at least 7-8 hours of sleep for the average adult.
Janet M. Mullington, Ph.D.
Professor of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School
Sleep helps us to avoid illness and recover when we are sick. People are 2 to 3 times more likely to become sick if they routinely get less than 6 or 7 hours of sleep per night. Sleep disturbance lowers our sensitivity to pain, and of course, pain can also disturb sleep.
The critical role of sleep in health
During the COVID pandemic, people who slept well (more than 7 hours of sleep per night on average), ate well, and exercised at least 150 minutes per week were 50% more resistant to developing chronic Long COVID conditions. People who had sleep apnea, the common respiratory sleep disorder where breathing is interrupted many times per hour through the night, were at increased risk for the development of Long COVID. However, those who were successfully treated for their sleep apnea had no increased risk for developing Long COVID.
Sleep also regulates metabolism, or the way our bodies make energy from the intake of food and drink. Sleep helps to control our body’s ability to absorb nutrients most efficiently. When we don’t get enough sleep for several days or more, our metabolism slows down. Slowed metabolism can lead to weight gain or the development of metabolic syndrome, associated with conditions including obesity, diabetes, and heart disease. Metabolic syndrome also leads to the development of more chronic conditions and diseases more common in aging, including dementia.
Sleep is not only important for the health maintenance of the middle-aged and elderly, but it is critical for the health of children, adolescents, and young adults. It is a secret ingredient for healthy growth and development, and also for learning and memory. In fact, sleep helps to develop emotional memory and balance, which are critical for mental health.
Sleep is a window into central nervous system health, helping to synchronize our many brain and bodily functions in 24-hour or “circadian” rhythms. An examination of one’s sleep can reveal warning signs for when health conditions are emerging. For instance, disorders of dream enactment may predict the development of Parkinson’s disease and other neurodegenerative diseases like dementia years before they are diagnosed.
Improving healthy sleep
Sleep is a behavior that can be influenced through practice and training. Cognitive behavioral therapy for insomnia effectively treats difficulty falling asleep or staying asleep, and these benefits can continue to accrue many months after the treatment is complete. Not unlike learning a musical instrument or improving physical fitness, improving sleep may take time, but with practice, it will improve. New technologies and data analysis methods are making it possible to learn more from wearable devices that track activity and sleep. More than a quarter of the population has some form of technology that enables them to track their steps, and now increasingly, sleep duration, nighttime temperature, heart rate, and estimates of blood oxygen that are summarized night after night.
How can knowledge about sleep and activity be used to help people achieve better health? This is an area of rapid development in the sleep and circadian research fields, with the promise of opening opportunities for improved remote health support for people in rural and remote parts of the country where access to healthcare may be challenging.
Research on sleep is supported by several agencies, including the National Institute on Aging, National Institute of Neurological Disorders and Stroke, National Institute of Child Health and Human Development, and National Heart, Lung, Blood and Sleep Institute. Other federal programs that support sleep research include the National Science Foundation, the Department of Defense, and the Veterans Administration. There are exciting opportunities for innovative research in sleep and circadian science across the lifespan that will help to reduce disease risk, support healthier aging, and promote better learning, memory, and a positive outlook. Sleeping well is an investment in health we can all benefit from!
