Reciprocal within-day associations between incidental affect and exercise: An EMA study

Previous research suggests that how people feel throughout the course of a day (i.e. incidental affect) is predictive of exercise behaviour. A mostly separate literature suggests that exercise can lead to more positive incidental affect. Objective: This study examines the potential reciprocal effects of incidental affect and exercise behaviour within the same day. Design: Fifty-nine low-active (exercise <60 min/week), overweight (BMI: 25.0-39.9) adults (ages 18-65) participated in a six-month print-based exercise promotion programme. Main outcome measures: Ecological momentary assessment was used to record self-reported exercise sessions in real time and incidental affective valence (feeling good/bad) as assessed by the 11-point Feeling Scale at random times throughout the day. Results: Use of a within-subjects cross-lagged, autoregressive model showed that participants were more likely to exercise on days when they experienced more positive incidental affect earlier in the day (b=.58, SE=.10, p<.01), and participants were more likely to experience more positive incidental affect on days when they had exercised (b=.26, SE=.03, p<.01), with the former association significantly stronger than the latter (t = 23.54, p<.01). Conclusion: The findings suggest a positive feedback loop whereby feeling good and exercising are reciprocally influential within the course of a day.