A 'Sit Less' program with Fitbit and text messages shows feasibility in cardiometabolic disease
Two parallel randomized controlled trials (n=35 completers) tested a 12-week intervention combining Fitbit tracking, text messaging, and brief counseling to reduce sedentary time in people with coronary artery disease or type 2 diabetes. The program showed high adherence and was associated with a reduction in hemoglobin A1c, though changes in sedentary time itself did not reach statistical significance.
People with cardiometabolic disease—cardiovascular disease or type 2 diabetes—typically spend 10 to 14 hours per day sedentary, which increases cardiovascular risk. Researchers conducted two parallel randomized controlled trials to test whether a "Sit Less" program could reduce sedentary behavior and improve health markers in this population.
The intervention included one in-person counseling session, a Fitbit device, a smart water bottle, and tailored text messages delivered over 12 weeks; the control group received standard American Heart Association written materials. Of 37 randomized participants, 35 completed the study (median age 67 years; 62% men), with baseline sedentary time averaging 10.4 hours per day. Sit Less participants showed excellent engagement: 81% responded to text messages and wore their Fitbit an average of 6.8 days per week for 15 hours daily, with 88% reporting satisfaction. Although reductions in total sedentary time (−17.3 minutes per day, not statistically significant) and prolonged sedentary bouts over 60 minutes (−49.9 minutes per day, P=.06) favored the intervention, they did not reach statistical significance. However, hemoglobin A1c—a marker of average blood glucose control—was significantly lower in the Sit Less group than control (−0.4%, P=.04). Other biomarkers and physical activity did not differ significantly between groups. The authors note the small sample size, limited statistical power, and wide confidence intervals as key limitations, but recommend evaluation in larger trials.
The trial's strength lies in its high real-world adherence rates: participants wore the Fitbit consistently and engaged with text messages at rates that suggest this type of intervention fits into daily life. Hemoglobin A1c dropped by 0.4% in the Sit Less group—a clinically meaningful reduction for people with diabetes, comparable to some single-agent medications. Subgroup analysis or secondary outcomes also showed trending improvements in continuous glucose monitoring metrics (mean glucose −6.0 mg/dL, P=.18) and time in target range, though these did not reach significance. Notably, self-efficacy for moderate physical activity was actually lower in the Sit Less group at follow-up (−0.6 points, P=.003), which the authors did not fully explain; this may reflect heightened awareness of activity gaps after receiving feedback, or measurement noise. The intervention's effect on total sedentary time was small and imprecise (wide confidence intervals), and the study was powered only to assess feasibility rather than efficacy. The control arm's minimal contact (booklet only) may have underestimated comparison effects if standard advice alone influences behavior.
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