Regularly sleeping more than eight and a half hours each night could be linked to early Alzheimer’s-related brain changes, new research suggests.
A US study published in the journal Alzheimer’s & Dementia analysed 2,410 participants from the Framingham Heart Study, with an average age of 70 years. Researchers found that those who reported sleeping more than eight and a half hours a night had higher blood levels of p-tau181, a biomarker strongly associated with Alzheimer’s disease.
Levels of the biomarker rose more sharply among those sleeping more than ten hours, even after researchers adjusted for factors such as age, sex, sleep apnoea and depression.
The researchers stressed that the findings do not suggest longer sleep causes Alzheimer’s. Instead, they believe it could be an early behavioural sign of underlying brain degeneration. The study’s author, Dr Vanessa Young, a postdoctoral research fellow at the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio, said the relationship between sleep and these biomarkers was unlikely to be simple, and that is exactly what they found.
The authors noted that self-reported sleep duration of more than nine to ten hours per night may warrant further assessment of sleep and cognitive health, and that long-term studies are needed to clarify the relationship.
