I love to sleep.
I have always loved to sleep. I feel much, much better after I sleep well. I became aware of this as a child. I began to treasure sleep quite early in life. I developed a regular sleep schedule. I learned that the best way to sleep well is to get plenty of exercise and go to bed physically tired.
One of the best things about being retired is never having to hear an alarm clock. Natural sleep, natural awakening. Aahhh!
Good sleep is a luxury that many Americans don’t enjoy. National data shows that poor sleep health is a common problem with 25 percent of U.S. adults reporting insufficient sleep or rest at least 15 out of every 30 days. The National Institutes of Health predicts that America’s sleep debt is on the rise and that by the middle of the 21st century more than 100 million Americans will have difficulty falling asleep.
Early sleep studies on animals and humans were pretty extreme. They don’t really apply to Macroeconomic impact.
The Macroeconomic question is: can common, ordinary sleep loss seriously affect the brain? Can sleep loss problems be cured by “making up” sleep later?
The answer is that ordinary (not extreme) chronic sleep loss does seriously affect the brain (in a mouse model). Amyloid and tau levels increase in the interstitial space in the hippocampus of wild-type mice in response to wakefulness and short-term sleep loss. (The hippocampus is the part of the brain that collects short-term memory.) Inflammation increased in the brain. Synapses were lost. These problems didn’t reverse after a long period of normal sleep after the sleep-deprivation experiment ended. A link to recent mouse research is in this linked article:
Mice aren’t humans, but longitudinal studies in people published over the past 15 years have relied on behavioral changes and self-reported sleep data to link chronic bad sleep to dementia, depression, metabolic issues, cardiovascular disease, insufficient immune response and even lower grade-point averages.
New microscopes have made it possible to observe the living brain during sleep. In 2012, the new microscopes discovered a waste-removal system in the brain, the glymphatic system, which removes toxins, tau proteins and amyloid-beta aggregates out of the brain. Glymphatic clearance mainly occurs in slow-wave sleep. In young adults, slow-wave sleep makes up between 10 and 25% of total sleep time, but this kind of sleep is not evenly distributed throughout the night, mostly occurring in the first half. Unfortunately, slow-wave sleep declines with age.
The vast majority Alzheimer’s patients have a shorter total sleep time and impaired slow-wave sleep, with both these deteriorations of sleep often predating its onset. It’s hard to say whether the onset of Alzheimer’s is caused by lack of sleep or whether people whose brain is becoming abnormal have shorter sleep as a result.
But I’d lay money that people who are sleep-deprived because of their jobs or other lifestyle reasons are increasing their risk of dementia. Years of building up garbage in the brain because the glymphatic system isn’t given enough time to sweep it out eventually takes its toll.
This has Macroeconomic impact because so many Americans are sleep-deprived and the cost of treating dementia is extremely high.
On the positive side, lifestyle choices such as exercise, omega-3 fatty acids and a low consumption of alcohol (0.5 g/kg) increased glymphatic clearance, reducing the risk of Alzheimer’s disease. (High alcohol consumption increases the risk of dementia).
Bottom line: Get 7 to 9 hours of sleep a night. Sleeping more later to make up sleep loss doesn’t work. Adopt lifestyle choices that are known to reduce the risk of dementia. The brain you save will be your own. As for America…expect more dementia later due to sleep deprivation, along with the Macroeconomic and personal costs.