Activity and mental well-being in older adults: a compositional data analysis (CoDA)

<p dir="ltr">This cross-sectional study investigated the relationship between daily time-use compositions of sleep, sedentary behaviour (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) and their associations with mental wellbeing in older adults aged 60–70 years. Using data from 380 community-dwelling participants and a compositional data analysis (CoDA) framework, our study examined how reallocations of time between these activities related to self-reported mental health outcomes, including depression, quality of life (QOL), and social network engagement. Accelerometer-derived estimates of time-use compositions were analysed alongside validated self-report questionnaires to produce a mental health composite score grounded in the dual continua model of mental health. Results indicated that reallocating 20 minutes per day to MVPA from any other behaviour was significantly associated with improvements in mental health composite scores, while reallocating time away from MVPA was associated with poorer mental health composite scores. Sleep and SB showed no direct associations with mental wellbeing, but their effects appeared context dependent. Interestingly, LPA showed no mental health benefit and was negatively associated with QOL. These findings highlight the unique role of MVPA in promoting mental wellbeing in older adults and support the value of compositional methods in generating more precise and actionable public health recommendations for healthy ageing in older adults.</p>