Why do we sleep?
It is a very interesting question that Dr. Matthew Walker explores in his recent book, "Why We Sleep." He highlights the buzz that would be created if scientists discovered something that made you live longer, be more creative and more attractive. It keeps you thin and reduces food cravings. It protects you from cancer, dementia, colds and flu. It lowers your risk of heart disease, strokes and diabetes. You will feel happier, less depressed, and less anxious. You would not be able to buy it fast enough no matter the cost and, yet, those are just a few of the advantages of a complete nights’ sleep.
What constitutes a complete nights’ sleep? Research has shown that adults require seven to eight hours of sleep a night to function optimally. Children require significantly more depending on their age. One of two people in America are sleep deprived. One of three routinely get less than six hours of sleep.
The average sleep in 1942 was 7.9 hours per night. Today, that number is 6.3 hours. The percentage of adults that can survive on six hours or less sleep without impairment is zero percent. A person going 10 days with six hours of sleep is impaired like a person that has 24 hrs of sleep deprivation.
You do not get used to the new level of sleep and level out or recover. You will always continue to perform impaired. People simply do not know how impaired they are if they are impaired. It is called “baseline resetting.” Over months, they reset to a new “normal.”
It is also a myth that you need less sleep as you age. We simply accept the deterioration of sleep because it happens slowly. Rarely do we connect the loss of sleep quality and quantity with the deterioration of our health or have physicians address the issue.
If you are the person that wakes up at 4:00 a.m. and reduces your sleep by two hours or 25 percent, there will be a 60 to 90 percent loss of REM sleep. REM is a wake-like brain signal where the thalamus allows signals of emotion, motivation, and problem-solving to be processed. Reduced REM can cause issues with anxiety, depression and pain. There is no major psychiatric condition where sleep is normal.
The body craves REM sleep and will attempt to resolve the deficit. People working at an REM deficit may experience an REM sleep rebound when they finally do get a good nights’ sleep. The body tires to replenish the deficit, and the dreams may be extremely intense. Alcoholics can have significant deficits of REM sleep due to the impact the alcohol has on sleep. When the alcohol is removed, delirium tremors in REM sleep rebound while awake.
Finally, one hour in bed on an iPad reading (as opposed to a book) and soft light delay melatonin release by three hours, resulting in being less refreshed the next day and a loss of REM sleep.
Instead of waking up in the middle of the night, what if you simply go to bed two hours later? In that case, you will rob yourself of a significant amount of non-REM sleep. In NREM sleep, we release hormones, recover physically from the day and move memories from short term to long term storage. In children, deep sleep refines brain development in the areas of cognition, critical thinking and reasoning. Increases in deep sleep always precede brain maturation.
Deep sleep also assists in weight management. People getting only five to six hours of sleep will require 200 to 300 extra calories per day. The serotonin centers in the brain will create a desire for high-carb, processed, sugary foods. As opposed to popular belief, serving sizes, processed foods and a sedentary lifestyle cannot explain the level of obesity today. Yet, the loss of two hours of sleep on average might.
The Catch 22 is that if you diet without sleep, 70 percent of the weight loss is from lean muscle mass, not fat. The body apparently assumes that if you are not sleeping, you must be foraging for food. In response, it increases fat stores.
Those trying to exercise when getting less than six hours of sleep will find a 10 to 30 percent reduction in time to physical exhaustion. Their aerobic output is reduced, limb extension force and vertical jump height reduced, lactic acid increases faster in the muscles, blood oxygenation is reduced, the ability to sweat is reduced and the risk of injury is increased. Whereas post-performance sleep increases the recovery from inflammation and increases muscle repair.
So why do we sleep? Because it is the key to physical and mental well-being. And yet we place so little emphasis on it.
People brag about being able to go long periods without sleep as if it were a badge of honor. Instead, we should value that time and work to help our patient heal. The book only superficially touches on the disruption to normal sleep that airway dysfunction can create. The parallels between his data on sleep loss and impacts of airway prosthodontics are staggering.
Jeff Rouse, D.D.S., Spear Faculty and Contributing Author