Sleep at Least Seven Hours Nightly to Power Wash Your Brain
April 5, 2023
Getting enough good quality sleep is beneficial to mood and memory. Recent studies also consistently show that sleep is critical for decreasing your risk of dementia and early death.
Harvard researchers studied 2,800 people 65 years of age or older to evaluate the link between sleep habits and the risk of developing dementia. They discovered that individuals who slept less than five hours per night were two times more likely to develop dementia and twice as likely to die from any cause during the five-year study, compared to those who slept six hours or more per night. Even after adjusting the data for demographic characteristics, including age, marital status, race, education, health conditions, and body weight, the people who did not get at least six hours of sleep per night were twice as likely to die during the study or to develop Alzheimer’s disease.
In another recent study, researchers from France, Britain, the Netherlands, and Finland evaluated data from 8,000 people and found that regularly sleeping less than six hours in middle age was linked to a 30% increased risk of dementia compared to people sleeping at least seven hours per night. This study measured sleep duration objectively using a wearable device that tracked their sleep using body movements which made the sleep data more accurate and reliable.
We all have justifications for not getting enough good sleep, such as work, captivating TV shows or sporting events, social media, caretaking duties, and insomnia, to name a few. Although some of these excuses are legitimate, many are flimsy. Time spent sleeping is among the most important and valuable times of all. We must prioritize our sleep because nearly everything else depends upon it. Get in the habit of getting to bed early. If you need to set an alarm to awaken in the morning, you are not going to bed early enough. Just keep moving your bedtime earlier until you wake up spontaneously and start your day refreshed and revitalized without an alarm.
Power Wash Your Brain
One of the likely reasons that inadequate sleep increases your risk of Alzheimer’s and dementia relates to the cumulative buildup of free radicals and protein debris in the brain. The brain is the most metabolically active organ of all. During waking hours, as it’s busy thinking and directing the show for your whole body, it burns a large quantity of fuel. Your brain weighs about three pounds—only about 2% of your total body weight— but it burns about 20% of the calories you consume. Like any fire, this generates a lot of metabolic “smoke and ash” in the form of free radicals and protein debris, like beta amyloid - toxic gunk that needs to be washed away nightly so that it doesn’t accumulate and eventually trash the brain.
Thankfully, during a long and deep night’s sleep, the glymphatic system flushes all this metabolic smoke and debris out of the brain. When we sleep, the neurons, glial cells, and blood vessels shrink substantially to open up a network of channels throughout the brain, allowing the watery cerebrospinal fluid to flow into all the nooks and crannies and wash away the nasty smoke and beta amyloid. If you don’t get enough sleep, your brain won’t have enough time to fully cleanse itself of the metabolic byproducts. Eventually, inadequate sleep causes the accumulation of this waste to the point that it interferes with the brain’s function, resulting in dementia.
Great News
The critical point is that getting adequate sleep will reduce your risk of developing dementia. A recent study showed that people who were at increased genetic risk of developing Alzheimer’s because of having one or two copies of the APOE4 gene had a lower risk of dementia if they got adequate amounts of high-quality sleep each night. Better sleep for these individuals not only lowered the likelihood of getting Alzheimer’s disease, it also reduced the development of tau tangles which are one of the pathologic hallmarks found in the brain of Alzheimer’s patients.
Bottom Line
Sleep isn’t merely a passive and inconvenient interruption in the fun and productive waking hours. Along with a nutritious diet and physically active lifestyle, sleep is one of the three pillars upon which long-term brain health is built. Emerging scientific data shows that inadequate sleep over time can eventually lead to Alzheimer’s and premature death, and the troubles can start in middle age. You can slash your risk of dementia by prioritizing seven to eight hours of nightly sleep. If you’re having issues with insomnia and you feel like you need a sleep aid, non-drug therapies like magnesium, melatonin, or baby aspirin taken before bedtime are your best options. Avoid prescription sleeping pills because they tend to be addictive and don’t promote the deep and restful sleep you need. The one prescription alternative that appears to be safe, effective, and non-habit forming is Trazadone.
Sleep in an essential part of life. But more important, sleep is a gift.
—William Dement
In Good Health,
James O'Keefe, MD
