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Can Bad Sleep Increase Your Risk of Dementia?

Adapted with links from an article written for The Brain Health Magazine

Sleep is arguably the most powerful and least expensive treatment that we have in our arsenal that can help support brain health. We all know this intrinsically, and most of us really do want to get more sleep. For most of us, getting a good night’s sleep helps us feel better throughout the day, but the latest research in neuroscience is showing us that patients who were sleep deprived had 1.68 times the risk for developing cognitive impairment or Alzheimer’s Disease.

 

In order to understand how sleep can impact our risk of dementia, we have to understand an important piece of anatomy called cerebrospinal fluid (CSF). CSF is a water-like substance that acts as a cushion inside of our head that serves to protect the brain from the jagged edges inside of the skull. CSF also plays a role in the transportation of nutrients and waste that can build up in the brain and spinal cord. From a clinician’s stand point, procedures like spinal taps are an important diagnostic tool because we can see if there’s evidence of infection of degeneration that has entered the brain.

 

The role of CSF in brain disease has gotten stronger recognition in the last decade and more recent neuroscience studies are pointing to a massive role of deep sleep. A groundbreaking study published in 2013 by Xie et al. showed that sleep increases the flow of CSF through a mouse brain, and that this increased flow cleaned removed the toxic protein clumps that are associated with Alzheimer’s disease. This system wasn’t working during the mouse’s awake phase.

 

Said another way, the system responsible for cleaning our brains of a toxic protein that causes Alzheimer’s Disease works primarily in sleep.

 

This was a massive finding that changed our understanding of why it feels like sleep is a powerful contributor to recovery. But does this effect happen in humans? So far, studies are saying yes. Three major papers corroborate some of the early findings that were seen in mice.

 

  1. A PET scan study by Shokri-Kojori et al on healthy patients showed that just one night of sleep deprivation increased the build up of beta-amyloid by 5%.

 

  1. A study by Fultz et al using functional MRI, EEG, and CSF flow measurements have identified an electrical signal that precedes a rush of increased spinal fluid movement during sleep.

 

  1. Finally, a longitudinal study by Lucey et al studied patients with Alzheimer’s disease and used sleep tracking data. They showed that there was a strong relationship between loss of deep sleep and greater Alzheimer’s pathology.

 

So what does this mean for patients with brain injury?

 

We know that a history of brain injury puts some patients at higher risk of neurodegenerative disease. While the big suspicion is that the brain damage itself contributes to the disease process, there’s also a possibility that other physiologic processes from brain injury could be drivers of dementia.

 

A well known phenomenon after concussion is an increased prevalence of sleep disorders following the injury. Patients with concussion have poorer sleep quality and feel worse on waking than patients without a concussion. There is also a variety of sleep disorders associated with concussion including sleep apnea, insomnia, circadian rhythm disruption, and narcolepsy. No matter what the disorder is, the end result is a loss of the healing potential of deep sleep.

 

This has become such an important issue in my clinic, that if any concussion patients have any reported problems with sleep, then I consider referring for a sleep study right away. Prevention of dementia and neurodegenerative disease is certainly a consideration, but a loss of sleep is also going to impair the results patients can get from post-concussion syndrome.

 

We can do some amazing things in rehabilitating the brain in patients with persistent concussion problems, but there will be barriers to cognition and pain improvement if the patient continues to sleep poorly.

1 rep max squat: a future biomarker for brain health?

When people think about growing new brain cells and optimizing brain health, they think about playing games like Sudoku or Luminosity. The idea being that we need mental games to flex our mental muscle.

The problem is that mental games like Sudoku and Luminosity have failed to demonstrate any meaningful evidence that it alters brain or cogntive function. They can make you good at Sudoku-related tasks or LUminosity-related games, but that’s about it.

There is one thing that has consistently shown improvements in cognitive, cellular, and neurological measures of brain function:

Exercise

A 2018 study showed that the dis-use of leg muscles was associated with decreased production of neural stem cells and decreased maturation of the supporting cells in the brain.

While this study was done in rats, it does help to explain some important phenomenon seen in humans.

Neurodegenerative Disease, Leg Exercises, and Stem Cells

Neurodegenerative diseases consist of brain and nervous system illnesses like multiple sclerosis, Parkinson’s Disease, an ALS. One of the big commonalities with this class of neurological disorders is that they they will eventually take away your independent ability to move.

Dr. Danielle Botaii, one of the authors of the study, wanted to investigate whether it was the gradual deterioration or the nervous system compromised muscular function, or if there was a possibility that loss of mobility from these diseases accelerated brain deterioration. [Source]

The study used mice and restricted the use of their hind legs and were compared to control mice who roamed normally. The researchers found that the mice who didn’t have normal use of their legs showed:

  • 70% decrease in neural stem cells compared to controls
  • Decreased maturation of support cells in the brain
  • Decreased expression of key genes for mitochondrial health

All of this to say that simply taking away the function of their legs could have significant ramifications for the ability of the brain to develop, adapt, and repair properly. With compromised stem cell production, less glial cell maturation, and worse energetics, you deal the brain a harder hand to play with. So much of our brain is built to provide action and resistance to gravity, and your legs play a huge role in that.

Squatting Your Way to a Better Brain

So the title of this article was definitely hyperbolic and click-baity. Guilty as charged. But the idea of squatting your way to better brain health sounds pretty sexy when you’re a doctor that lifts.

Working on that Snatch/Overhead Squat…..for brain health purposes

It’s super unlikely that your 1 rep max squat is going to be useful as a brain biomarker (though one can hope!), but there’s growing evidence that moving your legs frequently and often is phenomenal for your brain. One might even be able to make the case that running, jumping, squatting, and any other movement that keeps your legs strong may have more brain benefits than weight loss benefits.

There’s been ample evidence in mouse models that showed steady state running had significant effects on brain cell growth in a key memory area of the brain called the hippocampus. There’s also been compelling studies showing sedentary behavior reduced brain volume in parts of the brain which couldn’t be overcome by casual exercise.

There’s really no human evidence yet that shows that squatting will change the brain, but I feel strongly that preserving leg strength is one of those key things that differentiate those that age poorly and those that age with grace.

It’s definitely way too early, but I say we jump start the movement to 1RM for your Brain and let the evidence come in after the fact. Squat regularly and squat often friends.