Sleep, Alzheimer’s Disease and Yoga

by Nina

Sun Behind Clouds by Melina Meza

One of the worst fears I think we all share about getting older is of developing dementia. Just recently I had a long phone conversation with a woman who is trying to deal with a mother in the early stages of Alzheimer’s Disease, and it was just so sad. I had some advice for her, but no solutions, of course. Then I heard a news piece on NPR “Brains Sweep Themselves Clean of Toxins During Sleep”  that gave me  glimmer of hope.

Scientists have been trying to figure out the purpose of sleep for a very long time. A recent study “Sleep Drives Metabolite Clearance from the Adult Brain”  published in Science Magazine, proposed a fascinating new theory. The team of researchers from the University of Rochester discovered that while the brain sleeps it clears out harmful toxins, a process that may reduce the risk of Alzheimer's. According to the NPR interview, during sleep, the flow of cerebrospinal fluid in the brain increases dramatically, washing away harmful waste proteins that build up between brain cells during waking hours. Professor of Neurosurgery and an author of the study, Dr. Maiken Nedergaard, said, "It's like a dishwasher."

The waste proteins getting washed away during sleep are toxic to brain cells, which could explain why we don't think clearly after a sleepless night and why a prolonged lack of sleep can actually kill an animal or a person. The results appear to offer the best explanation yet of why animals and people need sleep.

“Thus, the restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.” Lulu Xie, et al.

Alzheimer's Disease researchers say this research could help explain a number of recent findings related to sleep and AD. Dr. Randall Bateman, Professor of Neurology  at Washington University said this about beta amyloid, which is the main component of certain deposits found in the brains of patients with Alzheimer's Disease.

"Beta amyloid concentrations continue to increase while a person is awake. And then after people go to sleep that concentration of beta amyloid decreases. This report provides a beautiful mechanism by which this may be happening.”

The team of scientists discovered the cleaning process while studying the brains of sleeping mice. Dr. Nedergaard said that during sleep the system that circulates cerebrospinal fluid through the brain and nervous system was "pumping fluid into the brain and removing fluid from the brain in a very rapid pace.” When the mice went to sleep, their brain cells actually shrank, making it easier for the fluid to circulate. But when the mice woke up, their brain cells enlarged again and the flow between cells slowed dramatically.

The researchers speculated that the reason the brain doesn’t do this cleaning all the time is because the cleaning uses a lot of energy, and it’s probably not possible for the brain both to clean itself and at the same time be aware of its surroundings, talk, move, and so on. So getting enough sleep—which we already know is vital for our physical and mental health—may be one key to preventing Alzheimer’s Disease as you age.

But what does all this have to do with yoga? Well, if you’re having trouble sleeping, yoga can help with that. Because insomnia is so often related to stress, yoga’s stress management techniques can help you quiet your nervous system so you fall asleep more quickly and sleep more soundly. For  information on how yoga can help you sleep better, see Yoga for Insomnia, Part 1  and Day to Night: Yoga for Better Sleep. The Supported Inverted poses I wrote about recently (see All About Supported Inversions) are poses that I've found particularly helpful.

We’re so careful here at YFHA not to make any false promises and of course as this research is new, we can’t promise that getting enough sleep will definitely make a difference for you. But encouraging you to get a good night’s sleep can’t be harmful in any way, and if this gives you more motivation to practice stress management techniques, which are helpful for preventing a whole host of health problems, we’re doing you a favor. And if you'd like to add an additional practices to encourage brain health, start meditating on a regular basis (see Meditation and Brain Strength) and keep practicing your yoga asanas (see Yoga for Brain Health?).