Working night shifts can raise the chances of Alzheimer’s disease by disrupting sleep and the body’s internal clock, leading to buildup of harmful brain proteins over time.
Night shifts force people to sleep during the day and stay awake at night, which messes with the natural sleep-wake cycle known as the circadian rhythm. This disruption does not just make you tired. It affects the brain in ways that link to Alzheimer’s. A study from Washington University School of Medicine found that even one night of poor sleep in healthy middle-aged adults boosts levels of amyloid beta, a protein tied to Alzheimer’s.https://medicine.washu.edu/news/sleep-alzheimers-link-explained/ After a full week of bad sleep, another protein called tau rises too, and tau damages brain cells in Alzheimer’s patients.
Experts like David M. Holtzman from that study say chronic poor sleep in middle age might increase Alzheimer’s risk later on. The brain clears out amyloid beta during deep sleep. When night shifts interrupt this, the protein sticks around and forms plaques that harm memory and thinking.https://medicine.washu.edu/news/sleep-alzheimers-link-explained/ Research in PubMed Central adds that long-term sleep loss speeds up brain aging and raises dementia risk, with as many as 15 percent of Alzheimer’s cases possibly linked to poor sleep.https://pmc.ncbi.nlm.nih.gov/articles/PMC12753350/
Shift work also weakens the internal body clock. A study noted that weaker rhythms and later activity peaks make dementia more likely by messing with brain processes and sleep quality.https://economictimes.com/news/new-updates/dementia-risk-associated-with-weak-internal-body-clock-study-suggests/articleshow/126353265.cms People with irregular schedules, like 12 to 35 percent of Americans on night or rotating shifts, face these issues often.
One bad night might not cause lasting harm, as protein levels can drop with good sleep the next time. But years of night shifts add up. Sleep apnea, common in shift workers, speeds up mild cognitive impairment by about 10 years, an early sign of Alzheimer’s.https://medicine.washu.edu/news/sleep-alzheimers-link-explained/ Night waking alone hurts next-day thinking, and over time, it ties to higher Alzheimer’s rates.https://www.psu.edu/news/health-and-human-development/story/night-waking-impacts-cognitive-performance-regardless-sleep
Naps might help some. Nurses on night shifts who took two-hour naps showed better memory and brain connections on scans, countering sleep loss effects.https://www.psypost.org/two-hour-naps-during-night-shifts-may-restore-brain-function-and-memory-in-nurses/ Still, experts stress fixing chronic problems matters most to protect the brain.
Sources
https://medicine.washu.edu/news/sleep-alzheimers-link-explained/
https://medicalxpress.com/news/2025-12-night-shifts-deadly-disrupted-linked.html
https://www.psypost.org/two-hour-naps-during-night-shifts-may-restore-brain-function-and-memory-in-nurses/
https://pmc.ncbi.nlm.nih.gov/articles/PMC12753350/
https://www.boomermagazine.com/sleep-and-dementia-connection/
https://www.psu.edu/news/health-and-human-development/story/night-waking-impacts-cognitive-performance-regardless-sleep
https://economictimes.com/news/new-updates/dementia-risk-associated-with-weak-internal-body-clock-study-suggests/articleshow/126353265.cms
