A recent study suggests that regularly sleeping more than eight and a half hours per night may be associated with early biological changes linked to Alzheimer’s disease. Researchers from the United States examined data from the Framingham Heart Study to explore the relationship between sleep duration and markers indicative of Alzheimer’s pathology.
The analysis included 2,410 participants with an average age of 70 years. Investigators measured blood levels of p-tau181, a protein biomarker strongly correlated with Alzheimer’s disease, and examined how these levels varied according to self-reported sleep duration. Results indicated that individuals who reported sleeping more than eight and a half hours nightly had elevated p-tau181 concentrations compared to those with shorter sleep durations. The increase was particularly pronounced among participants reporting more than ten hours of sleep.
The findings persisted after adjusting for potential confounders such as age, sex, presence of sleep apnea, and symptoms of depression. According to the study’s lead author, Dr. Vanessa Young, a postdoctoral research fellow at the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio, the relationship between sleep duration and Alzheimer’s biomarkers is complex and not necessarily straightforward.
Importantly, researchers emphasized that their results do not indicate that extended sleep causes Alzheimer’s disease. Instead, they propose that prolonged sleep may represent an early behavioral manifestation of underlying neurodegeneration. They recommend that individuals reporting habitual sleep durations exceeding nine to ten hours might benefit from further cognitive and sleep health assessments. The authors also called for longitudinal studies to better understand the direction and mechanisms underlying the association between sleep patterns and Alzheimer’s pathology.
Current guidelines from the UK’s National Health Service advise adults under 65 to aim for seven to nine hours of sleep per night, while those over 65 are generally recommended to get seven to eight hours. Alzheimer’s disease, the most common cause of dementia in the UK, affects approximately one million people, with around one in 14 individuals over 65 living with the condition. The progressive illness impairs memory, language, reasoning, and the ability to perform everyday activities.