Abstract
BACKGROUND: Physical activity is associated with both the hedonic (e.g., affect) and eudaimonic (e.g., purpose in life) aspects of well-being. While there is evidence linking momentary physical activity and affect in daily life, the examination of momentary purpose remains largely unexplored. PURPOSE: This study investigates the bidirectional associations between physical activity, positive and negative affect, and momentary purpose using Ecological Momentary Assessment (EMA) and accelerometer data. METHODS: Middle-aged participants (40-70 years old, n = 291) wore accelerometers and completed three daily EMA surveys on momentary experiences for 8 consecutive days. Physical activity (active time and counts) from 20- to 60-min periods before and after EMA surveys were used in the analyses. Multilevel models were adjusted for temporal and contextual factors, age, sex, education, work status, and race/ethnicity. RESULTS: When participants were more physically active than usual, they reported feeling more purpose-driven and positive affect. Similarly, when participants reported feeling more purpose-driven or experiencing positive affect, they engaged in more physical activity in the subsequent time period. These associations were similar for physical activity from 20- to 60-min periods before and after the EMA survey. Physical activity and negative affect were not related in either direction. CONCLUSIONS: In middle-aged adults' daily lives, physical activity has bidirectional relations with purpose and positive affect. This study highlights the dynamic associations between physical activity and the positive aspects of both hedonic and eudaimonic well-being. Future interventions or public health programs should integrate physical activity and mental well-being to maximize mutual benefits.