Sitting Time Reduction and Blood Pressure in Older Adults: A Randomized Clinical Trial

Abstract

Importance: Practical health promotion strategies for improving cardiometabolic health in older adults are needed.

Objective: To examine the efficacy of a sedentary behavior reduction intervention for reducing sitting time and improving blood pressure in older adults.

Design, setting, and participants: This parallel-group randomized clinical trial was conducted in adults aged 60 to 89 years with high sitting time and body mass index of 30 to 50 from January 1, 2019, to November 31, 2022, at a health care system in Washington State.

Intervention: Participants were randomized 1:1 to the sitting reduction intervention or a healthy living attention control condition for 6 months. Intervention participants received 10 health coaching contacts, sitting reduction goals, and a standing desk and fitness tracker to prompt sitting breaks. The attention control group received 10 health coaching contacts to set general healthy living goals, excluding physical activity or sedentary behavior.

Main outcomes and measures: The primary outcome, measured at baseline, 3 months, and 6 months, was sitting time assessed using accelerometers worn for 7 days at each time point. Coprimary outcomes were systolic and diastolic blood pressure measured at baseline and 6 months.

Results: A total of 283 participants (140 intervention and 143 control) were randomized (baseline mean [SD] age, 68.8 [6.2] years; 186 [65.7%] female; mean [SD] body mass index, 34.9 [4.7]). At baseline, 147 (51.9%) had a hypertension diagnosis and 97 (69.3%) took at least 1 antihypertensive medication. Sitting time was reduced, favoring the intervention arm, with a difference in the mean change of -31.44 min/d at 3 months (95% CI, -48.69 to -14.19 min/d; P < .001) and -31.85 min/d at 6 months (95% CI, -52.91 to -10.79 min/d; P = .003). Systolic blood pressure change was lower by 3.48 mm Hg, favoring the intervention arm at 6 months (95% CI, -6.68 to -0.28 mm Hg; P = .03). There were 6 serious adverse events in each arm and none were study related.

Conclusions and relevance: In this study of a 6-month sitting reduction intervention, older adults in the intervention reduced sedentary time by more than 30 min/d and reduced systolic blood pressure. Sitting reduction could be a promising approach to improve health in older adults.

Trial registration: ClinicalTrials.gov Identifier: NCT03739762.

Figure.. CONSORT Flow Diagram for the Healthy Aging Resources to Thrive (HART) Trial

EHR indicates electronic health record; KPWA, Kaiser Permanente Washington. ^aParticipants withdrawing from the overall study is a subset of those discontinuing the intervention (after 0 or ≥1 sessions). Reasons for study withdrawal by arm are as follows: I-STAND: no longer interested (n = 1), health reasons (n = 1), and personal or life circumstance (n = 1); healthy living: no longer interested (n = 3), time commitment (n = 3), and passive refusal (n = 1). ^bBaseline: outcome is missing or outcome at both month 3 and month 6 are missing. ^cBaseline covariates included in the regression model are missing.