More Evidence Linking Sleep to Alzheimer’s Disease

More Evidence Linking Sleep to Alzheimer’s Disease

Researchers at the University of Wisconsin-Madison found direct links between inadequate sleep in middle-aged, cognitively normal individuals and Alzheimer disease biomarkers. What is new about this study is that participants were younger and had not been diagnosed with dementia.

In this study, participants had lumbar punctures to provide cerebrospinal fluid (CSF) for an analysis. All the participants were cognitively normal. An analysis of the CSF biomarkers showed increased Alzheimer’s disease pathology in individuals with sleep problems.

 

Are CSF Biomarkers an Early Test for Alzheimer’s Disease?

The authors of this study caution that CSF biomarkers have not been validated as being able to predict future dementia. Both CST and PET brain imaging [positron emission tomography] are useful for studying the development of Alzheimer’s disease.

 

To Test or Not to Test?

Since there is no definitive cure for Alzheimer’s Disease, clinicians are reluctant to use CSF biomarker testing in cognitively normal individuals. That may change as there are treatments being tested in the preclinical stages of Alzheimer’s disease.

Even without testing there are many lifestyle risk factors that can be modified to improve or support brain health. Increased physical and mental activity, as well as good nutrition, are all areas of lifestyle where changes can improve brain health.

This study suggests that sleep could also be an area where we could reduce dementia risk.

 

Is Sleep a Modifiable Risk Factor?

One of the problems with this study is that the sleep problems were self-reported. The study opted for using subjective measures of sleep rather than objective assessment tools.

Prior studies have shown a link between sleep disorders and amyloid plaques, so having more objective linkages between CSF biomarkers and neurodegeneration would be helpful.

Looking at the research, there is no definitive study showing poor sleep as a precursor to developing Alzheimer’s disease. There are links but it is not clear if the disease progression causes the sleep problems or if the sleep problems cause the disease progression.

A third and more likely alternative is also possible. There may be a more complex interrelation between the disease and sleep problems. If that is the case, then improving sleep and sleep patterns will have a positive effect on brain health and reduce dementia risk.

 

The Role of Blue Light in Sleep

Exposure to light has a powerful effect on our sleep/wake cycle. Specialized cells in the retina of the eye are finely-tuned to respond to daylight. They tell the brain to stop producing melatonin and start producing hormones like cortisol. When light fades, the body begins to increase its production of melatonin. The problem is that the modern world is awash in lights that have the same wavelength as the lights that wake us up. So we are kept awake when our body should be transitioning to sleep.

Not only does exposure to night-time light keep us awake, there are studies suggesting that it may have a negative effect on long-term health.

An animal study at Ohio State University, showed that exposure to light for eight weeks had a measurable impact on the brain. Inflammation increased and neurotransmitters withered. The animals also showed ‘depressive like symptoms’ and had memory problems.  In this study, the light used was equivalent to a child’s nightlight.

While research in humans in still in its early stages, we are already seeing some evidence of the negative effect of night-time exposure to light. Female night shift workers have a 50% to 70% increase risk for developing breast cancer during their lifetime than their day-working counterparts.

 

Get More Light During the Day

Reducing light at night is important but so is getting more light exposure during the day.

Getting more light exposure during the day will have a positive impact on your internal sleep/wake cycle. This becomes problematic for many seniors, particularly those living in long term care or assisted living facilities. Most individuals in these settings rarely get outside. It is not surprising then to find high numbers of sleep problems in those settings.

While we wait for research to come to definitive conclusions about the impact of light at night on the brain, we can make some good choices right now.

Improve your brain health and sleep patterns by:

  1. Getting outside during the day for exposure to sunlight;
  2. Powering down electronics, like televisions, computers, phones, and e-readers after the dinner hour;
  3. Sleeping in a dark room or using an eye-mask to filter out light at night.

And if you want the ultimate summer recalibration for your brain – go camping for the weekend. Getting lots of natural sunlight during the day and no artificial light at night will have a significant impact on your sleep/wake cycle.