A new study suggests that obstructive sleep apnea—a condition that disrupts breathing during sleep—may harm parts of the brain important for memory. The damage seems to be linked to lower oxygen levels, especially during REM sleep, when the brain is highly active and memory processing occurs.
What Is Obstructive Sleep Apnea?
Obstructive sleep apnea (OSA) happens when muscles in the throat relax too much during sleep. This can block the airway and cause repeated awakenings throughout the night. These interruptions often lead to low oxygen levels, which may stress the brain and body.
REM sleep, the phase when dreaming mostly happens, plays a big role in memory consolidation and emotional processing. If REM sleep is disturbed, important brain functions may be affected.
Study Overview
Researchers from the University of California, Irvine, examined how sleep apnea may affect brain health in older adults. The study included 37 people with an average age of 73. None of the participants had memory problems at the start, and none were taking sleep medications.
- 24 participants were diagnosed with sleep apnea
- Each person completed overnight sleep tests to track oxygen levels
- Brain scans were done to measure brain structure
- Memory tests were given before and after sleep
The study was published in Neurology, the journal of the American Academy of Neurology.
Key Findings
Lower oxygen = more brain damage
People with lower oxygen levels during REM sleep had more white matter hyperintensities, which are bright spots on brain scans that signal damage to brain tissue. This kind of damage is often linked to problems with small blood vessels.
Memory-related brain areas were smaller
Those with more white matter damage also had smaller hippocampuses and thinner entorhinal cortexes—both important for forming and storing memories.
Memory test scores dropped
Participants who had thinner entorhinal cortexes performed worse on memory tests taken after sleep, suggesting that poor oxygen and brain damage may reduce the brain’s ability to store new information.
Why It Matters
The study offers new clues about how sleep problems may contribute to memory loss and aging-related brain decline, including conditions like Alzheimer’s disease. While the study did not prove that sleep apnea causes brain damage, it showed a strong link between low oxygen during sleep and changes in the brain.
Dr. Bryce Mander, the study’s lead author, said the results point to a possible pathway: low oxygen may damage blood vessels, which then harms brain areas linked to memory.
Study Limitations
The study was small, with only 37 people.
Most participants were White or Asian, so results may not apply to everyone.
It was an observational study, meaning it shows a connection but not direct cause and effect.
Researchers say larger, more diverse studies are needed to confirm these findings. Still, the results highlight the importance of treating sleep apnea early, especially in older adults. Protecting sleep health could be one way to support brain function and reduce memory problems later in life.
