PLOS One
Lack of physical activity, poor sleep tied to dementia risk
Clinical takeaway: Encourage middle-aged and older patients to meet standard physical activity guidelines (≥150 minutes/week of moderate activity), limit prolonged sedentary time (>8 hours/day), and aim for 7 to 8 hours of sleep nightly.
Lifestyle factors are increasingly recognized as modifiable contributors to long-term brain health, particularly given limited effective treatments for dementia.
In this systematic review and meta-analysis of 69 prospective cohort studies involving millions of adults aged 35 and older, researchers examined how physical activity, sedentary behavior, and sleep duration relate to subsequent dementia risk.
Regular physical activity was associated with a 25% lower risk of dementia. In contrast, sleeping less than 7 hours or more than 8 hours was associated with an 18% and 28% higher risk, respectively. Prolonged sitting (>8 hours per day) was also associated with a 27% higher risk, although based on fewer studies.
“Dementia develops over decades, and our findings suggest that everyday behaviors such as physical activity, time spent sitting, and sleep duration may be linked to dementia risk,” the authors noted.
Source: Oye-Somefun A, et al. PLOS One. April 8, 2026. The Relationships between physical activity, sedentary behaviour, sleep, and dementia