The Hidden Connection Between Sleep and Dementia

Dr. Rhonda Patrick here. Today we are going to talk about why sleep is so important for brain health. Close to 50 million people live with Alzheimer's disease or another form of dementia, a number expected to triple by 2050. But an exciting new study suggests that getting enough sleep could decrease your risk of developing these conditions by a lot. We, of course, know that sleep is essential for human health. Insufficient or fragmented sleep increases the risk of developing many chronic illnesses. So to look at the link between sleep and dementia, researchers drew on data from the National Health and Aging Trends Study, an ongoing study of older adults living in the U.S. More than 2,800 participants with an average age of 77 completed questionnaires about their sleep quality.

The researchers then followed them for 5 years to track how many of them were diagnosed with dementia or passed away from any cause. They found those who reported getting fewer than 5 hours of sleep per night had twice the risk of developing dementia than those that slept 7 to 8 hours per night. And those who took over 30 minutes to fall asleep had a 45% higher risk of developing dementia. The researchers also found that getting less than 5 hours of sleep per night, having daytime sleepiness, and taking regular naps were associated with increased mortality during those 5 years. These findings aren't surprising. The glymphatic system is activated in sleep, particularly during slow-wave or deep sleep.

It's a series of vessels that surround the brain and use cerebral spinal fluid to distribute compounds as well as push out toxic waste products and other cellular debris. One of these is amyloid beta, a protein that accumulates and forms plaques in the brain as we age. These plaques can interfere with synapses between neurons, which we think is a major factor in Alzheimer's disease. But research indicates these plaques can also inhibit deep sleep. So it may be a vicious cycle. Poor sleep promotes the buildup of amyloid beta plaques, which in turn promotes poor sleep, creating a feedback that has direct effects on brain health.

I previously sat down to speak with sleep expert Dr. Matthew Walker, who described how the glymphatic system works and how failure to get enough sleep, and especially deep sleep, affects brain function. The more beta amyloid that builds up in this central frontal part of the brain, the less the deep sleep that you have. The less amyloid-related deep sleep that you had, the more forgetful you were the next day rather than the more that you remembered. So this was the first part of the Alzheimer's sleep equation, which is that Alzheimer's disease attacks the deep sleep generating regions, and you have a diminution of deep sleep, which in turn blunts your learning and memory abilities, and you become more forgetful.

While sleep is the most important factor for activating the glymphatic system, omega-3 fatty acids from fish oil have been shown in animal research to enhance the clearance of amyloid beta by improving the glymphatic system. And exercise has also been shown to promote glymphatic clearance of amyloid beta in the brains of mice. Similarly, a small study demonstrated exercise improves some of the acute insulin resistance caused by poor sleep, suggesting that while exercise isn't a replacement for poor sleep, it can help counteract some of the effects of lost sleep. New research is focused on identifying critical windows in a person's life when interventions might improve sleep quality and build resilience to Alzheimer's. Here are a few things you can try to get a better night's sleep.

Keep the room temperature cool. Avoid bright light in the evening, but seek it in the morning. And limit caffeine and alcohol. And while it's tempting to turn to sleeping pills to get a better night's rest, Be careful. Some studies suggest that hypnotic drugs reduce brain plasticity in animals, and they are associated with an increased risk of cancer in humans. But if you chronically have trouble getting a good night's sleep or staying awake during the day, you should discuss that with your doctor. So prioritize that sleep hygiene. You'll feel better now, and it could help prevent serious chronic conditions in the future. I'm Dr. Rhonda Patrick, and I'll catch you next time. Bye. Hey guys, if you like this video, make sure you click subscribe. That way you don't miss the next one.