Objective: The objective of the present study was to investigate (a) if daily physical activity at the within-person level is related to four different core affects the same evening, (b) if core affects in the evening predict physical activity the following day, and (c) if physical activity predicts core affects the following day.

Design: A total of 166 university students were asked to complete the affect and physical activity measures once a day (in the evening), for seven days. Bivariate unconditional latent curve model analyses with structured residuals were performed to investigate the relations within days and across days between the core affects and physical activity.

Main outcome measures: Core affects and physical activity.

Results: Physical activity had positive within-day associations with pleasant-activated and pleasant-deactivated core affects and a negative within-day association with unpleasant-deactivated affective responses. There were, however, no statistically significant relations between core affects and physical activity across days.

Conclusion: These results highlight that the measurement interval might be an important factor that influences the association between core affects and physical activity behaviors. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group