Objective: Negative affect in daily life is linked to poorer mental and physical health. Activity could serve as an effective, low-cost intervention to improve affect. However, few prior studies have assessed physical activity and affect in everyday life, limiting the ecological validity of prior findings. This study investigates whether daily activity is associated with negative and positive evening affect in young adults.
Design: Young adults (N = 189, Mdn = 23.00) participated in an intensive longitudinal study over 10 consecutive days.
Main outcome measures: Participants wore accelerometers to objectively assess moderate-to-vigorous physical activity continuously throughout the day and reported their affect in time-stamped online evening diaries before going to sleep.
Results: On days when participants engaged in more activity than usual, they reported not only less depressed and angry evening affect but also more vigour and serenity in the evening.
Conclusion: Young adults showed both less negative and more positive affect on days with more activity. Physical activity is a promising health promotion strategy for physical and mental well-being.
Keywords: accelerometry; affect; intensive longitudinal design; physical activity; within-person association.