All of us have experienced foggy thinking from a bad night’s sleep. But for some, chronic poor sleep can be a brain health disaster.

What’s more, neuroscientists recently confirmed that millions of poor sleepers suffer from a common and often undiagnosed condition that dramatically increases your risk of Alzheimer’s disease.

I’m talking about sleep apnea.

“Obstructive sleep apnea (OSA) is destroying the health of millions of Americans, and the problem has only gotten worse over the last two decades,” reports Dr. Timothy Morgenthaler, a sleep medicine specialist at the Mayo Clinic.

For those with the condition, breathing repeatedly stops and starts during sleep and is a leading cause of snoring.

Because of the obesity epidemic, the number of people suffering from sleep apnea has soared to an estimated 25 million in the U.S. People with a healthy weight can develop sleep apnea, too, but those who are obese have excess fatty tissue in their tongues. As a result, the tongue can block the airway when muscles in the throat relax during sleep.

Sleep Apnea and Your Health

As if the fatigue and foggy thinking from poor sleep isn’t bad enough, sleep apnea can have devastating consequences to your overall health.

It increases the risk of high blood pressure, heart disease, stroke, diabetes, liver problems and road traffic accidents. It more than triples the risk of premature death.

The effects on brain chemistry are equally serious. Sleep apnea increases the risk of depression, and impairs cognition, memory, mood, and alertness. In short, this condition is a wrecking machine like no other.

Poor sleep has long been linked to Alzheimer’s, and because sleep apnea causes fragmented sleep, scientists have been pretty confident for years that it’s a cause of the disease. Now, a study from Australia has confirmed the link between sleep apnea and Alzheimer’s for the very first time.

Brain Plaques in Sleep Apnea and Alzheimer’s Disease

The hippocampal region and brainstem are areas where the early pathological changes of Alzheimer’s can be seen in the form of amyloid plaques and tau tangles.

So researchers from RMIT University in Melbourne studied hippocampal samples of 34 deceased people, average age 67, and the brainstem of 24 others, all with clinically verified sleep apnea. None had shown signs of cognitive impairment before they died.

Researchers found both amyloid and tau in the brainstem, but this did not correlate with the severity of sleep apnea. However, the quantity of amyloid plaques in the hippocampal area did indicate the severity of sleep apnea.

Their analysis, published in the journal Sleep in September, showed that amyloid begins in the same place and spreads in the same way in both sleep apnea and Alzheimer’s disease. Identical signs of brain damage in both disorders provides important confirmation that they’re linked.

Lead investigator Professor Stephen Robinson commented, “Our study is the first to find Alzheimer’s-like amyloid plaques in the brains of people with clinically-verified obstructive sleep apnea. It’s an important advance in our understanding of the links between these conditions.”

Other researchers have examined the link between sleep apnea and Alzheimer’s disease and uncovered similar findings.

Higher Levels of Tau

The Mayo Clinic published a study in the journal Neurology in April in which they used a PET scan on 292 cognitively healthy people aged 65 or older.

The scientists were looking for a build-up of tau – the toxic protein linked to Alzheimer’s – in the entorhinal cortex, a key memory area of the brain.

They then asked the participants’ bed partners to complete a questionnaire to assess whether they witnessed apneas during sleep. In other words, whether they noted if the participants snored, stopped breathing, or woke up abruptly with gasping or choking. These are all likely signs of sleep apnea.

Researchers identified 43 people with suspected sleep apnea. Then, they compared brain scans of those 43 with the 249 where apneas hadn’t been observed.

The suspected sleep apnea group had levels of tau that were a significant 4.5 percent higher.

“These results suggest a plausible mechanism that could contribute to cognitive impairment and the development of Alzheimer’s disease,” the researchers concluded.

The research begs the question: if people with sleep apnea in midlife are more likely to develop Alzheimer’s, and those with Alzheimer’s are more likely to have symptoms of sleep apnea, which comes first?

Does sleep apnea cause amyloid and tau to accumulate or does the build-up of amyloid and tau cause sleep apnea?

Unfortunately, none of the research to date is able to tell us for sure. But what all of the researchers do agree on is that sleep apnea needs to be treated immediately.

A Problem That Shouldn’t be Ignored—But is!

It’s estimated that 90 percent of people with sleep apnea remain undiagnosed, and since the condition can have serious consequences, it would be a good idea for bed partners to monitor each other.

Those without a partner should ask themselves whether they wake up feeling unrefreshed, with a very dry mouth or headache; feel sleepy during the day; fall asleep within ten minutes of watching TV; feel moody, irritable, can’t concentrate or perform tasks more slowly than they feel they should.

If so, it’s time to seek medical attention. Sleep labs are often located at major medical centers. A home-based device is also available that monitors breathing, airflow and blood oxygen levels during sleep.

The most common treatment for sleep apnea is a CPAP machine, which uses a hose and mask or nosepiece to deliver constant and steady air pressure. One in three people who use the device report that it has completely transformed their lives. And now we can add that it’s probably helped save their memories, too.

A good friend of mine who suffers from obesity and diabetes has used a CPAP machine for many years and has far exceeded predictions for how long he would live. Of course, he’s using other treatments for diabetes as well, but I’m certain the breathing aid has been a huge factor in his surprising survival and mental alertness.

Actually it wouldn’t be a bad idea for a great many seniors to receive supplemental oxygen while sleeping. It can give a huge boost to health. But I doubt if this is going to happen soon.


  1. https://aasm.org/rising-prevalence-of-sleep-apnea-in-u-s-threatens-public-health/
  2. https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-study-shows-sleep-apnea-may-be-
    tied-to-increased-alzheimers-biomarker-in-brain/
  3. https://www.rmit.edu.au/news/all-news/2020/sep/sleep-apnea-alzheimers

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