The Role of Mood and Stress for Physical Activity Intentions: Insights from Ecological Momentary Assessment

Background
Intentions play a crucial role in physical activity (PA) engagement. However, various internal and external factors can facilitate or impede the formation of intentions. Momentary affect is one of those internal factors but is often overlooked by the mostly between-person-based health behavior models due to its fluctuating nature. In this study, we use Ecological Momentary Assessment (EMA) to examine the relationship between internal states like mood and stress with PA intentions on a within-person, intra-day level. Our focus is to further understand how those internal states may impact the formation of PA intentions and ultimately influence behavior.

Methods
Each day, for three weeks, 41 healthy participants (aged 19-67) completed four EMA prompts on momentary affect and stress, as well as upcoming barriers (PA incompatible external circumstances) and PA intentions. We used generalized logistic mixed-effect modeling to test within-person antecedents of PA intentions.

Results
Perceived external barriers impeded the formation of PA intentions. Happy and active moods were positively associated with PA intentions, while relaxed and tired moods showed a negative association. Surprisingly, stress was positively associated with PA intentions.

Conclusion
Our study is the first to provide evidence that, on the within-person level, stress might even facilitate the formation of PA intentions. This suggests a need for a more nuanced understanding of the relationship between stress and health behavior intentions. Further, we found that both momentary affect and stress play a decisive role in the formation of PA intentions and, thus, are underrepresented in current health behavior models.