Results of the Sedentary Intervention Trial in Cardiac Rehabilitation (SIT-CR Study): A pilot randomized controlled trial.

BACKGROUND: Sedentary time (ST) is negatively associated with cardiometabolic health and fitness. Traditional cardiac rehabilitation (CR) programming may not significantly reduce ST. The objectives of the study were to assess the feasibility and practicality of activPAL devices for measuring ST in CR, and whether prompting cues to interrupt sedentary behaviour can decrease ST and improve clinical outcomes.

METHODS: An 8-week, two-arm pilot randomized controlled trial allocated coronary artery disease patients to either a control (usual care CR) or intervention (CR + sedentary prompts from an activPAL3-VT) group. Primary outcomes included: recruitment; acceptability; completion; and, adherence rates. Secondary outcomes included changes in: ST; physical activity (PA); cardiometabolic health; psychosocial health; and, fitness.

RESULTS: Forty participants (16 females; 19 intervention; 62 ± 10 years) were randomized. Outcome data were available for 95% of participants. All but one participant completed the full intervention. Most (73%) intervention participants felt the prompts had somewhat changed their sedentary behaviour. At baseline, participants spent 47% of their day sedentary. No significant group differences in changes for any of the ST, PA or fitness outcomes were observed. The mean group difference for post-intervention ST (controlling for baseline) was 30.3 min/day (95% CI: -51.7, 112.2) in favour of the intervention. The intervention group reported significantly better physical health and had a lower ratio of total cholesterol-to-high density lipoprotein when compared to controls.

CONCLUSIONS: It is feasible to use activPAL devices to measure ST in a CR setting. Further studies are needed to assess the effectiveness of multi-component sedentary behaviour interventions.