Time frame and perceived stress in the intention–planning–physical activity link.

OBJECTIVE: The study aims to investigate the influence of time frame and perceived stress on the relationship between intention, planning, and physical activity (PA) within the health action process approach framework. METHOD: = 21.1 years), which measured perceived stress from the previous week and intentions to do PA, action planning, and coping planning for the following week, a 21-day daily survey was conducted, recording participants' moderate-to-vigorous physical activity (MVPA) levels each day and their daily intention to do PA, as well as daily action and coping planning for the next day. Multilevel modeling was used to analyze the daily dynamics in the intention-planning-MVPA link, and mediation was used to analyze how predictors influenced MVPA levels over 1 week after the baseline assessment. Moderated mediation models were tested to examine the moderating role of perceived stress. RESULTS: The study found that action planning had a more immediate impact on daily MVPA while coping planning played a more significant role in mediating the relationship between intention and MVPA on a weekly basis. Perceived stress did not significantly moderate the intention-planning-behavior link in either time frame. CONCLUSION: These findings suggest that planning strategies may be tailored to specific time frames, with action planning having a larger impact on daily intentions while coping planning better supports weekly intentions. This research contributes to our understanding of health behavior and offers insights for interventions to promote PA. (PsycInfo Database Record (c) 2025 APA, all rights reserved).