AHA Scientific Sessions 2026 Abstract · Nov 2, 2026
Feasibility, Acceptability, and Preliminary Effects of a Temporal Self-Regulation Theory-Based Behavioral Change Intervention on Accelerometer-Measured Sedentary Behavior: A Pilot Randomized Controlled Trial
By Miu EYN, Chair SY, Yeung WK et al.
Background: Although physical activity (PA) is a class I recommendation for secondary prevention of coronary heart disease (CHD), adherence remains suboptimal. Inadequate PA and prolonged sedentary behavior (SB) are independent risk factors, yet SB is frequently overlooked. These challenges underscore the need for theory-driven interventions targeting movement behaviors (MB), including increasing PA and replacing SB with activities of varying intensities during waking hours. Temporal Self-regulation Theory (TST) posits that behavior is shaped within a dual-process framework, whereby intention strength interacts with executive function (conscious planning and goal-directed action) and behavioural prepotency (habitual and automatic influences). Purpose: To assess the feasibility, acceptability, and preliminary effect of the TST-based behavioral change intervention on accelerometer-measured SB in individuals with CHD. Methods: This two-arm, single-blind, pilot randomized controlled trial was conducted at a regional hospital (November 2025-April 2026) using convenience sampling. Participants were randomized (1:1) to a 3-month intervention or active control. The intervention group received eight individual sessions plus an accelerometer-based MB report to support behavioral change, while controls received time-matched sessions without MB-related content. Feasibility (recruitment, attrition, completion rates), acceptability (structured interviews and satisfaction scales), and preliminary effects at immediate post-intervention were assessed. Outcomes included sedentary time, moderate-intensity PA time, and process-related measures. Between-group comparisons were analyzed using independent t-test, with Hedges’ g effect size estimated from change scores. Qualitative data were analyzed using content analysis. Results: A total of 30 adults with CHD were recruited (recruitment rate: 41.7%), with a 7% attrition rate. All participants in the intervention group completed all sessions. Mean age was 67.2±7.9 years, and 77% were males. Perceived benefits were reported by 92% of participants. At 3 months, sedentary time (minutes/day) decreased by –35.1±51.1 in the intervention group compared with an increase of 12.9±39.3 in the control arm (Hedges’ g=1.03). Moderate-intensity PA time (minutes/week) increased by 50.0±78.1 in the intervention group versus 6.8 ± 42.0 in the control group (Hedges’ g=0.67). Medium effect sizes were also observed for future time perception (Hedges’ g=0.74), behavioral prepotency (Hedges’ g=0.60), and intention for SB reduction (Hedges’ g=0.60). Conclusions: The intervention was feasible, acceptable, and yielded clinically meaningful reductions in sedentary time over the 3-month study period. A larger clinical trial with a longer follow-up duration is warranted to confirm effectiveness and assess sustainability.