One of the easiest and most important things you can do to improve your memory and reduce your dementia risk is to go to bed at a regular time every night and sleep well.
If you’re a long-time subscriber to this newsletter, then you’ve likely heard me tout the memory benefits of sleep many times before. Now, a recent study reveals another reason why sleep is so critical to memory and, even more important, how much sleep you really need.
Psychologists at the University of California, Berkeley, recently studied sleep habits in relation to maintaining a healthy brain as you age.
The research team found that poor sleep is linked to changes in the brain that are connected to the development of Alzheimer’s disease. For example, they found that people who report a declining quality of sleep as they age from their 50s to their 60s have more amyloid beta protein tangles in their brain, putting them at higher risk of developing Alzheimer’s disease.
“Insufficient sleep across the lifespan is significantly predictive of your development of Alzheimer’s disease pathology in the brain,” said the study’s senior author, Matthew Walker, a sleep researcher and professor of psychology.
It seems when it comes to sleep, there’s a sweet spot. Too little is detrimental, but so is too much.
How Much Sleep is Enough?
The authors of this new study understood that disrupted sleep is common in later years. And when sleep changes occur, so do changes to cognitive function -- the mental capacity for learning, thinking, reasoning, problem-solving, decision-making, remembering and paying attention can all become negatively affected.
The team found that both ends of the sleep duration spectrum could have varying effects on older adults’ brain health.
The Ideal Sleep Range
Those in the study who operated on a sleep deficit – six hours or less – had elevated levels of amyloid beta that "greatly increases" risk for dementia. (There is research that questions the link between amyloid beta and Alzheimer’s disease - although this is still the accepted belief in the medical community.)
The researchers compared this group of short sleepers to participants who reported normal sleep patterns, which the researchers defined as seven to eight hours of sleep per night.
So what did they learn?
The older adults with insufficient sleep performed moderately to significantly worse on tests commonly used for assessing cognitive abilities, memory, language, visual-spatial skills and identifying mild dementia.
And what about those snoozers who reported sleeping nine or more hours a night? Researchers said that while this group did display lesser executive function, they did not have elevated amyloid beta levels.
Make Time for Sleep
"The main takeaway is that it is important to maintain healthy sleep late in life," Mr. Winer said. "Additionally, both people who get too little sleep and people who get too much sleep had a higher body-mass index (BMI) and more depressive symptoms."
He added that the findings suggested that both short and long duration sleep might involve different underlying disease processes. But the presence of amyloid beta (amyloid-β) is of utmost concern.
He notes that about 30 percent of healthy 70-year-olds will have substantial amounts of amyloid plaques in their brain. Not only do many healthy adults have high levels of the plaques, but many people with dementia don’t have them. What’s more, drugs that target amyloid-beta plaques have not been successful in treating dementia. Having said that, it’s well-known that poor-quality sleep increases dementia risk and that lack of sleep physically alters the brain.
As with most self-reported studies, this one has its limitations. However, some interesting patterns did emerge. For instance, both the short and long-sleep duration groups reported more depressive symptoms than the normal sleep group.
While self-reported caffeine intake didn’t appear to influence sleep, alcohol consumption did. It seems the more alcoholic drinks participants drank daily, the more likely they were to sleep longer.
If you need some guidance to improve your sleep habits, then try these tips from the Sleep Foundation at https://www.sleepfoundation.org/sleep-hygiene.
If you need help falling asleep and staying asleep throughout the night, try our 100% herbal and natural SleepMEND product. It is a great alternative to melatonin supplements.