United States: In a new study published May 7 in the journal Neurology documented by the National Institute of Neurological Disorders and Stroke, there is a scary connection between sleep apnea and cognitive decline. Scientists discovered that declines in blood oxygen levels during sleep apnea episodes are especially detrimental for brain areas associated with memory and learning during REM sleep, as reported by HealthDay.
REM Sleep
REM sleep, the stage of sleep associated with dreaming and memory consolidation, appears to be particularly vulnerable. “Our results show that the lower a person’s oxygen levels drop during REM sleep due to sleep apnea, the more serious the brain degeneration,” said researcher Jeffery Breitenfeld.
Oxygen Loss Damages White Matter and Memory Centers
The study analyzed brain scans and sleep data from 37 individuals (average age 73), 24 of whom had sleep apnea. Those with more time spent below 90% blood oxygen during REM sleep showed greater damage to white matter—the brain’s communication network that supports memory. They also had smaller hippocampus and entorhinal cortex regions, both vital for memory function.
Sleep Apnea May Harm Brain Areas Key to Memory
— Neuroscience News (@NeuroscienceNew) May 7, 2025
A new study links obstructive sleep apnea to damage in brain regions vital for memory, driven by low oxygen levels during REM sleep.
Researchers found that participants with more severe oxygen drops had higher levels of white… pic.twitter.com/iVePzUIfgG
Small Vessel Damage Could Be the Missing Link
Senior researcher Bryce Mander, associate professor at the University of California-Irvine, explained that low oxygen during sleep may damage small blood vessels in the brain. This damage then leads to degeneration in areas that manage memory consolidation—potentially increasing the risk of Alzheimer’s disease and other forms of dementia.
A Growing Concern with Age
Obstructive sleep apnea increases with age and may remain undiscovered in numerous people. The condition leads to breathing interruptions when one is sleeping, causing oxygen levels to decrease, and disrupts the normal sleep processes in the brain, as reported by HealthDay.
Not Definitive—But Deeply Concerning
Although the researchers do not establish that sleep apnea directly causes brain degeneration, the link can not be overlooked. Unaddressed sleep apnea has the potential to affect brain health negatively in the long term, based on the evidence.