By Dr. Kritika Joshi, DO
Chronic insomnia is a very common problem I see as a PCP. While we all know that a poor night’s sleep leaves us foggy the next day, research shows that chronic sleep problems can increase the risk of dementia, including Alzheimer’s disease.
Let’s look at what high-quality studies from 2024-2025 are teaching us — and how new research on medications like semaglutide (Ozempic) may also influence brain aging.
Long-term studies consistently find that chronic insomnia or fragmented sleep is linked with higher dementia risk.
A 2024 meta-analysis in GeroScience reviewing 39 cohort studies found that insomnia increased dementia risk by 36% and sleep apnea by 33% compared to people without these sleep disorders (PubMed ID: 40214959).
These results are observational but show a strong and consistent association across large populations.
During deep sleep, the brain clears beta-amyloid, a toxic protein that accumulates in Alzheimer’s disease. Without this nightly cleanup, brain aging may accelerate.
Sleep apnea — a condition where breathing stops repeatedly during sleep — is one of the most underdiagnosed health issues in adults.
A review published in Sleep Medicine Reviews found that untreated sleep apnea may raise Alzheimer’s risk by up to 45%. The combination of low oxygen and nighttime awakenings increases inflammation and may damage brain blood vessels.
The good news: treating sleep apnea helps. Using a CPAP machine or other therapies improves oxygen flow, reduces inflammation, and protects long-term brain function.
Getting the “right” amount of sleep also matters.
A systematic review in Aging Research Reviews found that both short sleep (<6 hours) and long sleep (>9 hours) were linked with greater cognitive decline. The optimal range for most adults appears to be 7–8 hours of quality sleep nightly (PubMed ID: 31604673).
Beyond sleep, metabolic health plays a key role in brain longevity. One exciting area of research involves GLP-1 receptor agonists, such as semaglutide, known commercially as Ozempic or Wegovy.
A 2024 study published in Alzheimer’s & Dementia analyzed data from more than 1 million U.S. patients with type 2 diabetes and found that those taking semaglutide had a significantly lower risk of developing Alzheimer’s disease compared with patients on other diabetes medications (PubMed ID: 39445596).
Researchers believe semaglutide may help protect the brain by reducing inflammation, improving blood vessel function, and enhancing insulin sensitivity — all factors linked to Alzheimer’s risk.
While more research is needed, these findings highlight the connection between metabolic health and brain health — a core focus in healthspan optimization.
Here are science-backed steps you can take to support both sleep and brain longevity:
Screen for sleep disorders: If you snore, gasp, or wake up unrefreshed, get tested for sleep apnea — even mild forms can matter.
Set a consistent sleep routine: Go to bed and wake up at the same time every day.
Create a calm environment: Keep your room dark, cool, and quiet. Limit screen time and caffeine close to bedtime.
Move and eat for brain health: Exercise regularly, follow a Mediterranean-style diet, and limit alcohol.
Manage metabolic health: Controlling blood sugar, weight, and inflammation all support cognitive longevity — and may enhance sleep quality too.
Healthy sleep isn’t just about feeling rested — it’s a pillar of long-term brain health. Peer-reviewed research shows that poor sleep, insomnia, and sleep apnea increase dementia risk. At the same time, emerging studies suggest that medications like semaglutide may offer new ways to protect the brain through better metabolic control.
In good health,
Dr. Joshi
