Department of Epidemiology and Biostatistics (B.B.G.), West Virginia University, Morgantown.
Departments of Medicine and Biostatistics (S.P.), University of Pittsburgh, PA.
Circulation. 2024 Oct 29;150(18):1416-1427. doi: 10.1161/CIRCULATIONAHA.123.068564. Epub 2024 Aug 21.
Sedentary behavior (SB) is observationally associated with cardiovascular disease risk. However, randomized clinical trials testing causation are limited. We hypothesized that reducing SB would decrease blood pressure (BP) and pulse wave velocity (PWV) in sedentary adults.
This parallel-arm, 3-month randomized clinical trial recruited desk workers, age 18 to 65 years, with systolic BP 120 to 159 or diastolic BP (DBP) 80 to 99 mm Hg, off antihypertensive medications, and reporting <150 min/wk of moderate to vigorous intensity physical activity. Participants were randomized to a SB reduction intervention or a no-contact control group. The intervention sought to replace 2 to 4 h/d of SB with standing and stepping through coaching, a wrist-worn activity prompter, and a sit-stand desk. SB and physical activity were measured with a thigh-worn accelerometer and quantified during all waking hours and separately during work and nonwork times. Clinic-based resting systolic BP (primary outcome) and DBP, 24-hour ambulatory BP, and PWV were assessed by blinded technicians at baseline and 3 months.
Participants (n=271) had a mean age of 45 years and systolic BP/DBP 129/83 mm Hg. Compared with controls, intervention participants reduced SB (-1.15±0.17 h/d), increased standing (0.94±0.14 h/d), and increased stepping (5.4±2.4 min/d; all <0.05). SB and activity changes mainly occurred during work time and were below the goal. The intervention did not reduce BP or PWV in the intervention group compared with controls. Between-group differences in resting systolic BP and DBP changes were -0.22±0.90 (=0.808) and 0.13±0.61 mm Hg (=0.827), respectively. The findings were similarly null for ambulatory BP and PWV. Decreases in work-time SB were associated with favorable reductions in resting DBP (r=0.15, =0.017). Contrary to our hypotheses, reductions in work-time SB (r=-0.19, =0.006) and increases in work-time standing (r=0.17, =0.011) were associated with unfavorable increases in carotid-femoral PWV. As expected, increases in nonwork-time standing were favorably associated with carotid-femoral PWV (r=-0.14, =0.038).
A 3-month intervention that decreased SB and increased standing by ≈1 hour during the work day was not effective for reducing BP. Future directions include examining effects of interventions reducing SB through activity other than work-time standing and clarifying association between standing and PWV in opposite directions for work and nonwork time.
URL: https://www.clinicaltrials.gov; Unique identifier: NCT03307343.
久坐行为与心血管疾病风险呈观察性相关。然而，测试因果关系的随机临床试验有限。我们假设减少久坐行为会降低久坐成年人的血压（BP）和脉搏波速度（PWV）。
这项平行臂、3 个月随机临床试验招募了年龄在 18 至 65 岁之间、收缩压为 120 至 159 或舒张压（DBP）为 80 至 99mmHg、未服用降压药物且报告每周中高强度体力活动时间<150 分钟的久坐上班族。参与者被随机分配到久坐行为减少干预组或无接触对照组。干预措施旨在通过教练、手腕活动提示器和可坐站两用办公桌，将每天 2 至 4 小时的久坐行为转换为站立和走动。使用大腿佩戴式加速度计测量和量化所有清醒时间和工作时间及非工作时间的久坐行为和身体活动。由经过培训的技术人员在基线和 3 个月时进行诊室静息收缩压（主要结局）、舒张压、24 小时动态血压和 PWV 评估。
参与者（n=271）的平均年龄为 45 岁，收缩压/舒张压为 129/83mmHg。与对照组相比，干预组参与者减少了久坐时间（-1.15±0.17 小时/天），增加了站立时间（0.94±0.14 小时/天），增加了走动时间（5.4±2.4 分钟/天；均<0.05）。SB 和活动的变化主要发生在工作时间，且低于目标值。与对照组相比，干预组的血压或 PWV 均未降低。干预组静息收缩压和舒张压变化的组间差异分别为-0.22±0.90（=0.808）和 0.13±0.61mm Hg（=0.827）。与静息血压和 PWV 类似，动态血压也无明显变化。工作时间 SB 减少与静息 DBP 有利降低相关（r=0.15，=0.017）。与我们的假设相反，工作时间 SB 减少（r=-0.19，=0.006）和工作时间站立增加（r=0.17，=0.011）与颈动脉-股动脉 PWV 不利增加相关。如预期的那样，非工作时间站立增加与颈动脉-股动脉 PWV 呈有利相关（r=-0.14，=0.038）。
为期 3 个月的干预措施减少了工作日期间的 SB 并增加了约 1 小时的站立时间，但并未有效降低血压。未来的研究方向包括研究通过非工作时间站立以外的活动来减少 SB 的干预措施的效果，并阐明站立与 PWV 之间在工作和非工作时间呈相反方向的关联。
