Brain agingHumans

Stronger rest-activity rhythms link to better executive function

Across 169 older adults followed over three years, stronger 24-hour activity rhythms tracked with better executive function and reduced risk of mild cognitive impairment.

Frontiers in Aging Neuroscience4 Oct 2026, 08:24 BST

In 169 older adults from the BIOCARD study, researchers examined 24-hour rest-activity rhythms using repeated seven-day wrist actigraphy over an average of 3.2 years. They analyzed how rhythm regularity, fragmentation, and day-night contrast related to executive function, plasma biomarkers, and clinical progression.

Higher person-average day-night contrast and regularity, alongside lower fragmentation, were associated with superior executive function. At the visit level, exceeding one's own average contrast and having lower fragmentation correlated with better concurrent cognitive performance. Greater average contrast also predicted a lower risk of incident mild cognitive impairment (hazard ratio 0.499). Rest-activity metrics showed no significant associations with plasma biomarkers of Alzheimer's disease or neurodegeneration. However, amyloid PET status amplified the within-person associations: visit-level rhythm improvements corresponded more strongly to higher executive function in amyloid-positive individuals.

Why it matters

Circadian disruption and fragmented sleep-wake cycles are key features of biological aging and neurodegenerative disease. These findings show that maintaining robust daily activity cycles correlates with preserved cognitive performance, particularly in adults harboring Alzheimer's pathology.

Caveats

The observational design assessed cognitive tests and activity metrics concurrently, meaning it cannot determine whether rhythm changes directly cause cognitive differences. Additionally, the cohort was predominantly female and highly educated, and only 12 participants developed mild cognitive impairment during follow-up.