Why sleep is good for you and your brain!

Dr Matthew Walker, neuroscientist and author of Why We Sleep says, “sleep unfortunately is not an optional lifestyle luxury, it is a non-negotiable necessity and it is your life-support system. It is mother nature’s best effort at immortality.”[1] Sleep is one of the six tips in maintaining a healthy brain, 7-9 hours a night is the recommended number of hours for optimal results. Sleep not only helps maintain your immunity, your cardiovascular health, and keep your genes in tip top shape, it could also lead to a new preventative therapy for dementia.[2]

In 2012 Dr Jeff Iliff, PhD led a research team that discovered and defined the glymphatic system as the network of pathways that supports the clearance of waste from brain tissue during sleep. Iliff’s experiments found that the glymphatic system mediates the transport of Alzheimer’s-associated proteins out of the brain. This process appears to slow with age and in the presence of vascular and traumatic brain injury. Since then, research from around the world has confirmed that this “janitorial” work is happening in the human brain!

So why is sleep, and a deep sleep, so important as we age? Iliff’s research has shown that the bulk of glymphatic clearance occurs during deep sleep when slow wave activity is most abundant. It is well known, he says, that people sleep less and less, and more poorly as they get older, therefore that deep sleep and slow wave activity is not happening as much. This then prevents the glymphatic system, which acts as a “brain rinsing” cycle, from working thoroughly. Iliff’s research suggests that “this slowed or decreased clearance might set the stage for the development of neurodegeneration”. Therefore, obtaining a better night’s sleep, that includes a deep sleep, is ideal to stave off cognitive decline and neurodegenerative diseases such as Alzheimer’s and dementia.

Another study done by Dr Matthew Walker also concentrates on sleep. In a TedTalk from 2019, Dr Walker discussed the benefits of a good night’s sleep for not only the brain but also cardiovascular health, immunity, genes and reproductive organs. It is all interrelated.

In Walker’s research it is suggested that a key part of the brain that is affected by sleep (either a good night’s sleep or a lack of sleep) is the hippocampus. He describes it as the “information inbox” which receives new memories and helps us hold onto them. When we sleep the hippocampus can store these memories and new learnings from the day and actively prepare for a new day of learning and memories ahead. When we don’t get enough sleep though, the ability to learn new skills and develop new memories is lessened by almost 40%. Additionally, Walker’s study suggests that the disruption of deep sleep is an underappreciated factor that is contributing to cognitive decline in ageing and in Alzheimer’s disease.

So, what can we do to obtain better sleep? Both Dr Matthew Walker and Dr Jeff Iliff have some suggestions for us,

1. Have a routine for your sleep, go to bed at the same time and wake up at the same time every day no matter if it is the weekend or during the week.
2. Sleep in a cool place. The body needs to drop a couple degrees to fall asleep and stay asleep. Typically, 18 C is the ideal temperature for everyone.
3. Avoid or decrease substances that are clearly harmful for sleep such as stimulants, caffeine, tobacco and alcohol.

[1] https://www.ted.com/talks/matt_walker_sleep_is_your_superpower?utm_campaign=tedspread&utm_medium=referral&utm_source=tedcomshare

[2] http://depts.washington.edu/mbwc/news/article/the-cleansing-power-of-a-deep-nights-sleep