Effect of Reducing Sedentary Behavior on Blood Pressure (RESET BP): Rationale, design, and methods

Abstract

Sedentary behavior (SB) has recently been recognized as a strong risk factor for cardiovascular disease, with new guidelines encouraging adults to 'sit less, move more.' Yet, there are few randomized trials demonstrating that reducing SB improves cardiovascular health. The Effect of Reducing Sedentary Behavior on Blood Pressure (RESET BP) randomized clinical trial addresses this gap by testing the effect of a 3-month SB reduction intervention on resting systolic BP. Secondary outcomes include other BP measures, pulse wave velocity, plasma renin activity and aldosterone, and objectively-measured SB (via thigh-mounted activPAL) and physical activity (via waist-worn GT3X accelerometer). RESET BP has a targeted recruitment of 300 adults with desk jobs, along with elevated, non-medicated BP (systolic BP 120-159 mmHg or diastolic BP 80-99 mmHg) and physical inactivity (self-reported aerobic physical activity below recommended levels). The multi-component intervention promotes 2-4 fewer hours of SB per day by replacing sitting with standing and light-intensity movement breaks. Participants assigned to the intervention condition receive a sit-stand desk attachment, a wrist-worn activity prompter, behavioral counseling every two weeks (alternating in-person and phone), and twice-weekly automated text messages. Herein, we review the study rationale, describe and evaluate recruitment strategies based on enrollment to date, and detail the intervention and assessment protocols. We also document our mid-trial adaptations to participant recruitment, intervention deployment, and outcome assessments due to the intervening COVID-19 pandemic. Our research methods, experiences to date, and COVID-specific accommodations could inform other research studying BP and hypertension or targeting working populations, including those seeking remote methods.

Figure 1.

Flowchart of study visits

Figure 2.. BP Measurement Protocol

All measurements occur in the morning (6:00 AM – 11:00 AM), using an HEM-907 XL oscillometric BP monitor and an appropriately sized cuff, and following a 10-minute seated rest with proper arm positioning, back supported, and feet flat, a verbally confirmed 8-hour abstention from food, caffeine and nicotine, and a 24-hour abstention from MVPA and alcohol.

Figure 3.

Recruitment sources for the first 2276 referrals

Figure 4.

Reasons for ineligibility after phone screen (panel A; N=1921) and after informed consent (panel B; N=153)