Abstract 13463: Effect of an Intervention to Reduce Sedentary Behavior on Blood Pressure in Desk Workers: The RESET BP Randomized Clinical Trial (RCT)

Introduction: High sedentary behavior (SB) is associated with cardiovascular (CV) risk in cohort studies, yet definitive data from RCTs of SB reduction on CV risk factors is lacking.

Hypothesis: A 3-month SB reduction intervention would decrease blood pressure (BP) and pulse wave velocity (PWV) in sedentary adults.

Methods: We recruited desk workers with systolic BP (SBP) 120-159 mmHg or diastolic BP (DBP) 80-99 mmHg, not on antihypertensives, and reporting low physical activity. Participants were randomized 1:1 to a 3-month SB reduction intervention or control. The intervention targeted replacing sitting with standing and stepping via health coaching, a wrist-worn activity prompter, and a height-adjustable workstation. All day and work-specific SB, standing, stepping, and steps were measured by a thigh-worn triaxial accelerometer. Protocolized office SBP (primary outcome), DBP, and HR were measured in duplicate on two occasions at each baseline and 3 months; 24-hr ambulatory BP and carotid-femoral PWV via tonometry were also measured. Changes in outcomes were compared across groups using analysis of covariance and mixed models.

Results: Participants (n=271) had mean age 45 y and BP 129/83 mmHg; 60% were female and 82% were non-Hispanic White. Retention was 97%. Intervention participants reduced SB during work (-1.3 hr/day) and across all waking hours (-1.1 hr/day) compared to controls (both p<0.001). Intervention participants increased work-specific standing (1.2 hr/day), stepping (5 min/day) and steps (398/day) and all day standing (1.0 hr/day), stepping (7 min/day) and steps (528/day) compared to control (all p<0.05). Yet, the intervention did not yield a greater reduction in BP or PWV vs. controls (all p>0.05). Differences in changes were office SBP -0.24 mmHg (p=0.793), DBP 0.08 mmHg (p=0.894), and heart rate -2.75 (p=0.190). Findings were similar for 24-hr, daytime, and nighttime ambulatory BP averages (all <1.2 mmHg; p>0.05). Differences in PWV were higher (opposite from the hypothesized direction) in intervention vs. control and approached significance (0.18 m/s, p=0.07).

Conclusions: In sedentary desk workers with mild-moderate untreated BP, this 3-month intervention reduced daily SB by about one hour but did not improve BP or PWV.