Introduction: The social and physical context of physical activity may each influence its association with individuals’ momentary affective states. However, there is limited evidence investigating the real-time joint effect of context and physical activity on momentary affect, and it is unclear whether such joint effect varies among individuals from different cultures. This study used ecological momentary assessments (EMA) to examine the real-time joint effect of physical activity, social context, and physical context on affective states in the US and Indian college students, and examine any cultural differences.

Methods: This study involved 218 college students (US: n=158; India: n=60) with an average age of 19.99 (SD=1.14). Participants received surveys 6 semi-random times per day over 7 consecutive days between 2021 and 2023 via a smartphone application. The surveys measured momentary affect (negative and positive), physical activity, social context, and physical context. Multilevel structural equation models were used for analysis in Mplus (V8.9).

Results: Analysis of 5,820 EMA surveys revealed that at the within-person level, being not alone (vs alone) and moving (vs sitting) were associated with both increased momentary positive affect and decreased negative affect, while being outdoors (vs indoors) and standing (vs sitting) were associated only with increased momentary positive affect. Analysis of joint effect showed that students reported the lowest negative affect while engaging in higher levels of physical activity (i.e. moving) with someone (vs alone), and while being outdoors with someone (vs alone). Highest positive affect and lowest negative affect were also reported while sitting outdoors (vs indoors). Analysis of regional differences indicated that while both regions experienced a lower negative affect being outdoors, the effect was more pronounced for Indian college students.

Conclusions: Findings of this study may encourage further investigation of other more complex joint contextual effects on psychological well-being. It will also inform the refinement of existing just-in-time adaptive interventions to target the real-time joint contexts for delivering mental health interventions. For instance, promoting physical activity when individuals are outdoors and not alone may elevate benefits for reducing negative affect. Future studies also need to replicate the contextual effects using larger and more diverse populations.