To identify latent classes of time spent in movement activities (leisure sitting, physical activities, and sleep), characterize them, and assess their association with changes in memory, executive functioning, and overall cognition among middle aged and older adults.

Longitudinal cohort study with a 3-year follow-up.

Non-institutionalized middle aged and older adults from the general population.

12,212 adults aged 45 to 86 years from the Canadian Longitudinal Study on Aging.

Latent Class Analysis was performed to identify groups of participants with comparable movement activities based on self-reported time spent in leisure sitting, walking, moderate and vigorous physical activity (assessed using the Physical Activity Scale for the Elderly), and sleep at baseline. Multivariable linear regression models were used to examine the associations between the identified groups and reliable change in memory, executive functioning and overall cognition, measured by a validated neuropsychological battery including 6 different cognitive tests.

Three groups were identified: Sedentary/Disturbed Sleep (SedDS, 53.9%), Intermediately Active/Normal Sleep (IntNS, 34.6%), and Active/Normal Sleep (ActNS, 11.5%). The SedDS group showed greater cognitive decline after 3 year follow-up across all cognitive domains (memory β=-0.061, 95%CI -0.100, -0.021; executive functioning β=-0.049, 95%CI -0.090, -0.008; overall cognition β=-0.067, 95%CI-0.106, -0.027) compared to IntNS. Interestingly, ActNS showed a greater cognitive decline (memory β=-0.065, 95% CI -0.124, -0.005; overall cognition β=-0.062, 95% CI -0.123, -0.002) relative to IntNS.

In mid- and later life, sleep disturbances primarily coincide with a sedentary lifestyle. For optimal cognitive ageing, moderate physical activity seems more beneficial than either sedentary behavior or excessive physical activity to delay accelerated cognitive ageing.