Sleep and the Connection to Dementia and Alzheimer’s

A healthy brain relies on 7-9 hours of sleep for younger to middle age individuals and 7-8 hours for older adults. This is because full sleep cycles take about 120 minutes to cycle through each stage of sleep. If you do not have enough hours of sleep, you will not cycle through each stage enough times for the brain to perform the health and tasks it needs to while you sleep.

Poor sleep can be linked to stroke, cognitive decline, and dementia. Overall brain health can be assessed by cognitive testing and evaluation. But it can also be assessed using biomarkers in the blood. These levels shown by biomarkers, when they get high, play a role in causing strokes or Dementias like Alzheimers Disease.

There is a significant association with long sleep (greater than 8 hours) that is associated with stroke. While short sleep (less than 7 hours) has a less significant correlation statistically. This means that there was a significant increase in clinical subjects who consistently slept longer than 8 hours and an increased likelihood of stroke in those subjects. Persistent long sleeps were according to this study are considered a significant possible marker for future stroke (2. Leng).

What Does The Brain Do During Sleep:

Throughout life, the brain builds up certain proteins that can become degenerative and can be correlated to Dementia. Typically, a system within the body will function highly efficiently at night to expel these proteins from the brain or to keep them functioning like they should be. This is called the glymphatic system. In short, the glymphatic system heightens and works overtime while you are in a deep sleep, this helps to clean up the brain and to prevent excessive build up of dementia causing proteins in the brain.

The problem is, if an individual lacks sleep, then the glymphatic system does not work as efficiently as it could during a deep sleep. This allows for the build up of degenerative proteins or neurotoxins that are not expelled during sleep. As a result, this can lead to dementia or Alzheimer's.