A doctor once lamented that he had difficulty getting his patients to exercise more to avoid heart attacks. However, when he told his patients that poor sleep was associated with the development of Alzheimer’s Disease, they immediately adopted healthy sleeping habits. The threat of heart attacks didn’t scare them, but dementia did!

How is sleep related to Alzheimer’s Disease, or risk factors for Alzheimer’s? And how might getting a good night’s sleep regularly protect you?

Quality vs Quantity

A 2013 study looked at the relationship among:

  • sleep efficiency (the percent of time in bed asleep)
  • sleep quantity (total sleep time )
  • frequent naps (three or more days per week)
  • the accumulation of beta-amyloid plaque (a risk factor for Alzheimer’s).

The scientists found that the accumulation of beta-amyloid plaque, and hence the risk for Alzheimer’s, was associated with:

  • less sleep efficiency
  • greater sleep quantity
  • frequent naps

In short, too much sleep―either as overnight sleep or naps―increases risks, but quality sleep reduces them.

Confirmation from Other Studies

Other investigations also found benefits associated with good sleep―whether it is defined as sleep efficiency, or as uninterrupted slumber during the slow-wave stages of a night’s sleep. For example, studies show that people with:

  • the most (vs the least) amyloid plaque in their brains had worse sleep, as measured in the lab, and did worse on a memory test
  • regular (vs no) reported sleep disturbances were one-and-a-half times more likely to develop Alzheimer’s
  • a single copy of the apolipoprotein E (APOE) gene (that is, carriers of a genetic risk factor for Alzheimer’s) increased their risk nearly seven-fold if they reported sleep disturbance.

Why You Might Be Able To Protect Yourself Against Alzheimer’s

Lancet, the most influential journal in the world after New England Journal of Medicine, commissioned a group of experts to recommend how to best manage, and prevent, dementia. In 2017, the group came up with ten key messages, including, “Be ambitious about prevention.”

This advice stemmed from the conclusion that up to a third of dementia cases might be delayed or prevented―a discovery sparked by studies which found:

  • the incidence of dementia was decreasing in developed countries
  • this decline was correlated with improvements in cardiovascular health
  • autopsies of people who died without having Alzheimer’s had 24% less amyloid plaque in their brains if they died recently (vs up to several decades ago).

Improvements in health in developed countries have reduced, and might continue to reduce, the incidence of Alzheimer’s Disease. Consequently, one route to avoiding Alzheimer’s might involve better healthcare.

How To Reduce Your Risk of Getting Alzheimer’s

No one has a magic list of things to do to avoid getting Alzheimer’s. However, you can reduce your risk factors for Alzheimer’s significantly by multiple actions. These might include:

  • improving your sleep
  • reducing depression if you have it
  • avoiding obesity, and diabetes
  • not smoking.

Taking care of these basic building blocks of good health will be much more cost effective than medications in the pipeline. That is because these drugs, if effective for mild Alzheimer’s, will have only small effects in reducing plaque, and will be very expensive. Prevention studies that alter risk factors, on the other hand, create reductions of 22 to 44%.

For More Information

Tips for Improving Sleep

Key Research

Other Resources

  • alzforum.org, a non-profit network of researchers who study Alzheimer’s Disease, and use this site to post articles and comments
  • CET’s self-assessments to help you assess your mood and sleep

Elizabeth Saenger, PhD