People typically equate sleeping with “doing” nothing. But your internal system works like a busy pit crew when you come to a halt. After you’ve put your body through a day of wear and tear, it uses your downtime to replace cells, heal wounds, build muscle, detoxify organs, clean the bloodstream, and consolidate memories.
In 2019, Boston University researchers uncovered a critical activity taking place when you snooze. Blood flows out of your brain and cerebrospinal fluid flows in, “washing through your brain in rhythmic, pulsing waves” — essentially flushing toxic, memory-impairing proteins.
“If you are getting insufficient sleep to allow this to occur,” says Dr. Talene Churukian, a sleep medicine specialist at Eisenhower Health, “those proteins can build up and form plaque. That’s the culprit behind dementia.”
She notes a 2015 consensus statement from the American Academy of Sleep Medicine and Sleep Research Society that adults need a minimum of seven hours of sleep each night for optimal physical and mental health.
ILLUSTRATION BY KOTRYNA ZUKAUSKAITE
The sleep cycle involves four stages of brain activity, ranging from the light, stage 1 level to what is called rapid eye movement (REM) sleep that takes place at the deepest level. Churukian says that stage 1 should account for only about 5 percent of a night’s dormancy, stage 2 roughly 50 percent, and stage 3 and REM at least 20 percent each.
“We usually have three to five REM cycles a night,” she explains, noting that it takes 90 to 120 minutes to transition through the first three phases. “You need seven hours of sleep to achieve that. Every stage has a specific function. With a shorter duration of sleep, even if it is good quality, you are cutting yourself short in not making it through the cycles you need for restoration.”
After a night of insufficient sleep, a nap may be helpful, but it should be well timed, Churukian advises. Following the body’s 24-hour circadian rhythm, she says, “It’s best to nap early in the day, preferably before 3 p.m. Sleeping later in the afternoon reduces the physiological sleep drive.” For someone with chronic insomnia, she adds, merely dozing off can “perpetuate that disruption.”
Our requirement for sleep does not dissipate as we age. Unfortunately, what happens is that the cycles “break down,” Churukian says, pointing to factors such as arthritic pain and a decrease in bladder capacity that awaken us.
Furthermore, the brain’s pineal gland, which serves as a cue for the biological clock, produces less melatonin with age and certain conditions, including Alzheimer’s disease.
“Deviant circadian rhythms and poor sleep quality are associated with increased risks of cardiovascular, metabolic, and cognitive diseases; poor quality of life; and mortality,” states a 2018 article in the British Journal of Pharmacology. “As a result of the recently discovered relationship between circadian clock, sleep, and neurodegeneration, new prospects of using melatonin for early intervention to promote healthy physical and mental aging are of prime interest.”
Ensuring you get quality sleep involves more than lying your head on a pillow. Churukian describes a healthy sleep regimen as one that includes regular sleep and wake-up times, daily light exposure and exercise, a healthy diet, stress relief, a wind down prior to bedtime, and a bedroom kept cool at night.
Making the most of the hours you spend in bed can be as critical to your well-being as is capitalizing on the time you are awake. A healthy life is a dreamy one.
challenge
Adjust your daily routine to make duration — and, thus, quality — of sleep a priority.
