Sleep apnea is a disorder characterized by repeated pauses or shallowing of breathing during sleep. It is quite common in the general population. With each pause in breathing, blood oxygen levels drop, and the brain responds with brief awakenings. This cycle repeats many times throughout the night and disrupts sleep quality.
The relationship between sleep apnea and dementia has been increasingly studied in recent years. Sleep apnea occurs five times more often in Alzheimer's patients than in healthy individuals of the same age. The risk of sleep apnea increases by twenty-eight percent in those with Alzheimer's disease and by thirty-four percent in those with any type of dementia.
The higher occurrence of dementia in people with sleep apnea has been linked to several causes. The intermittent hypoxia that occurs during pauses in breathing increases reactive oxygen species in the brain. This damages neurons, triggers inflammatory processes, and sets the stage for cell death. At the same time, fragmented sleep disrupts the brain's waste-clearance system. This system removes harmful proteins such as amyloid-beta from brain tissue during sleep. When sleep is fragmented, this clearance process falters, and harmful proteins begin to accumulate in the brain.
Sleep apnea has also been linked to neurodegenerative processes in children. In children with obesity and a diagnosis of sleep apnea, levels of amyloid-beta and presenilin-1, two proteins associated with Alzheimer's disease, were found to be elevated. These levels decreased markedly after tonsil and adenoid surgery.
Sleep apnea is treated with positive airway pressure devices. When used regularly, this treatment reduces daytime sleepiness and improves sleep quality. It has also been shown to reduce biomarkers associated with Alzheimer's disease. In patients with mild cognitive impairment, treatment has been reported to slow cognitive decline.
Sleep apnea is not merely a nighttime complaint. It is a condition that affects brain health in the long term and increases the risk of dementia. Evaluating people who snore, experience nighttime breathing pauses, or complain of excessive daytime sleepiness in a sleep laboratory is important for both quality of life and neurodegenerative disease risk.
References
Branson CO. Sleep and Neurodegeneration. Continuum (Minneap Minn) 2026;32(4, Sleep Neurology):1142-1160.
Guay-Gagnon M, Vat S, Forget MF, et al. Sleep apnea and the risk of dementia: a systematic review and meta-analysis. J Sleep Res 2022;31(5):e13589.
O'Hara R, Schröder CM, Kraemer HC, et al. Nocturnal sleep apnea/hypopnea is associated with lower memory performance in APOE epsilon4 carriers. Neurology 2005;65(4):642-644.
