JMIR Publications

ABSTRACT

Background:

Individuals with cardiometabolic disease typically average 10-14 hours of daily sedentary time, which increases the risk for cardiovascular disease (CVD).

Objective:

To evaluate the feasibility, acceptability, and preliminary efficacy of a “Sit Less” program in reducing sedentary behavior in people with cardiometabolic disease.

Methods:

Participants with CVD or type 2 diabetes (T2D) underwent separate randomization into the Sit Less intervention or control group. Sit Less included one in-person counseling session, a Fitbit, a smart water bottle, and tailored weekly text messages for 12 weeks. Control group participants received the American Heart Association’s “Answers by Heart” booklet. Sedentary behavior was measured using activPAL for 7 days at baseline and post-intervention. Secondary outcomes included physical activity, cardiometabolic biomarkers, continuous glucose monitoring (CGM) metrics, and psychological factors. Generalized linear models estimated adjusted between-group differences controlling for baseline values, cohort, cohort × group interaction, and leisure-time exercise.

Results:

Of 37 randomized participants, 35 (95%) completed the study (Sit Less: 17; Control: 18). Of the 35 that completed the study, 62% were male, median age was 67 years, and their baseline sedentary time was approximately 10.4 hours/day. Sit Less participants demonstrated high adherence, including a text response rate of 81% and median Fitbit wear of 15 hours/day on 6.8 days/week, and 15 out of 17 participants (88%) reported satisfaction with the program. Compared with the control group, Sit Less participants showed greater reductions in total sedentary time (adjusted mean difference −17.3 min/day, 95% CI −63 to 28; P=.45), prolonged sedentary time >30 minutes (−39.5 min/day, 95% CI −100 to 21; P=.20) and >60 minutes (−49.9 min/day, 95% CI −102 to 2; P=.06), and increases in sit-to-stand transitions (4.2/day, 95% CI −2 to 10; P=.13), although none were statistically significant. Hemoglobin A1c (HbA1c) was significantly lower in the Sit Less group (−0.4%, 95% CI −0.8 to −0.1; P=.04). HbA1c was significantly lower in the Sit Less group compared with the control group (adjusted mean difference −0.4%, 95% CI −0.8 to −0.1; P=.04). CGM outcomes, including mean glucose (−6.0 mg/dL, 95% CI −14.9 to 2.8; P=.18) and time in range (2.1%, 95% CI −4.8 to 9.1; P=.54), were not statistically significant but demonstrated similar directional changes. Other cardiometabolic biomarkers, physical activity, and psychological outcomes were not significantly different, except for lower self-efficacy for moderate physical activity in the Sit Less group (−0.6, 95% CI −1.1 to −0.2; P=.003).

Conclusions:

The Sit Less intervention was feasible and acceptable and showed consistent directional improvements in sedentary behavior and a significant reduction in HbA1c. Although this study was underpowered and confidence intervals were wide, these findings support evaluation in larger, adequately powered trials. Clinical Trial: ClinicalTrials.gov NCT05534256 https://clinicaltrials.gov/study/NCT05534256 NCT05691452 https://clinicaltrials.gov/study/NCT05691452