Impacts of Reducing Sitting Time or Increasing Sit-to-Stand Transitions on Blood Pressure and Glucose Regulation in Postmenopausal Women: Three-Arm Randomized Controlled Trial.

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Standing up and sitting back down more often throughout the day may help lower diastolic blood pressure in overweight/obese postmenopausal women within three months.

Introduction

The study aimed to evaluate the physiological impact of two intervention arms (reducing sitting time vs increasing sit-to-stand transitions [STST]) on blood pressure and glucose regulation, compared to the control group among overweight/obese sedentary postmenopausal women.

Method

This three-arm randomised controlled trial enrolled 407 participants (aged 55 to 91 years) who were randomised (1:1:1) into the sit-less (n=136), increase STST (n=136), or healthy living (n=135) arms. Participants received 7 coaching sessions (5 in person and 2 by phone). The primary outcomes were glucoregulatory (insulin, glucose, HbA1c, and HOMA2-IR) and blood pressure markers assessed at baseline and 3 months.

Results

• The sit less group significantly reduced total daily sitting time by 58 minutes (baseline: 654 minutes/day; 3 months: 579 minutes/day) compared with the healthy living group (baseline: 669 minutes; 3 months: 652 minutes) (95% CI, –82.92 to –33.59; P<0.001).

• The STST group significantly increased daily STST by 26/ day (baseline: 45/day; 3 months: 71/day) compared with the healthy living group (baseline: 43/day; 3 months: 43/day) (95% CI, 17.71 to 33.64; P<0.001).

• At baseline, there were no significant differences between the three groups in blood pressure or glucose regulation outcomes.

• At baseline, HbA1c differed significantly between the three groups (P=0.001) with mean (SD) values of 5.80 (0.76) in the healthy living group; 5.64 (0.53) in the sit-less group and 5.54 (0.36) in the STST group.

• The STST group showed a significant reduction in diastolic blood pressure compared with the healthy living group (-2.24 mm Hg; 95% CI, -4.08 to -0.40; P=0.02). However, although systolic blood pressure decreased (–3.33 mm Hg; 95% CI, –6.32 to –0.33; P=0.03), it did not meet the prespecified statistical significance level.

• No intervention effects on glucoregulatory biomarkers (insulin, glucose, HbA1c, and HOMA2-IR) were observed in either intervention group compared to the healthy living group (P>0.05).

Conclusion

Postmenopausal women are at high risk of prolonged sedentary behaviour and cardiovascular disease. Increasing STST reduced diastolic blood pressure within 3 months, supporting the effectiveness of interventions targeting sitting behaviours in this population.

• Healthcare practitioners working with overweight/obese postmenopausal women could recommend increasing STST throughout the day to support diastolic blood pressure management.

• When supporting sedentary individuals, it is important to distinguish between total sitting time and STST frequency to better guide targeted health interventions.

• Future studies with longer follow-up periods are needed to better observe sizeable physiological changes.

• Study population focused on overweight/obese women and lacked racial and ethnic diversity. Thus, future research should enrol ethnically diverse participants, and clinical populations with prehypertension or prediabetes to better identify differences in glucoregulatory outcomes.

• Continuous glucose monitoring may be used to better understand the association between sedentary behaviour and glucoregulatory outcomes.

• Further research should also assess diet and sleep in order to evaluate their potential impact on the study outcomes.