According to a study by researchers working with the American Academy of Neurology, published in the journal Neurology, individuals who snore and/or suffer sleep apnea - a condition that leads to loud snoring and difficulty breathing - face a higher risk of stroke, Alzheimer’s disease, and overall cognitive decline. Symptoms also include breathing interruptions, choking and gasping sounds, and restlessness during sleep.

A separate study by the Faculty of Medicine at the University of Paris-Cité, France, says that for every 10% decrease in the amount of sleep, the brain ages 2.3 years older, while in every five individuals (20.2%) suffering such a disorder, only 3.5% are receiving treatment.

Biomarkers in the brain's white matter are crucial for connecting different parts of the brain, such as tiny lesions, known as white matter hyperintensities, which can be seen on brain scans and become more abundant with age or uncontrolled high blood pressure.

In a press release, Dr. Diego Carvalho from the Mayo Clinic stated, “These biomarkers are sensitive indicators of early cerebrovascular disease. Finding that severe sleep apnea and a reduction in slow-wave sleep are associated with these biomarkers is important since there is no treatment for these changes in the brain, so we need to find ways to prevent them from happening or getting worse".

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140 participants with obstructive sleep apnea with an average age of 73 partook in the study, undergoing brain scans and an overnight stay at a sleep lab. None of the participants were suffering cognitive issues at the start of the study, nor were they suffering from dementia at the time. 

“More research is required to ascertain if sleep issues affect these brain biomarkers or if it’s the other way around. We also need to explore whether improving sleep quality or treating sleep apnea can affect the trajectory of these biomarkers,” says Dr. Carvalho.

The research found that for every 10% decrease in deep sleep, the white matter hyperintensities went up to equate to 2.3 years of aging. Those suffering from severe sleep apnea had more white matter hyperintensities than those with mild or moderate conditions and thus showed a plunge in the integrity of their brain’s axons that connect nerve cells.

Dr. Pauline Balagny from the University of Paris-Cité explains: “We know that Obstructive Sleep Apnea (OSA) is a significant health risk. But if patients are diagnosed with this condition, they can receive treatments and advice to mitigate the risks".

“Our study implies that OSA is common, but the majority of those affected are unaware they have the condition.”

Researchers from the University of California-Berkeley supported the research findings with their own, discovering that enough amounts of deep sleep can protect older adults from Alzheimer’s-related memory loss, since participants with high amounts of amyloid deposits in their brain performed better on the memory test than those with the same levels of deposits who slept insufficiently.

According to UC Berkeley professor of neuroscience Matthew Walker, deep sleep is like " a life raft that keeps memory afloat, rather than memory getting dragged down by the weight of Alzheimer’s disease pathology".

“It now seems that deep NREM sleep may be a new, missing piece in the explanatory puzzle of cognitive reserve. This is especially exciting because we can do something about it. There are ways we can improve sleep, even in older adults.”