The effects of prolonged sitting, prolonged standing, and activity breaks on vascular function, and postprandial glucose and insulin responses: A randomised crossover trial

Abstract

The objective of this study was to compare acute effects of prolonged sitting, prolonged standing and sitting interrupted with regular activity breaks on vascular function and postprandial glucose metabolism. In a randomized cross-over trial, 18 adults completed: 1. Prolonged Sitting; 2. Prolonged Standing and 3. Sitting with 2-min walking (5 km/h, 10% incline) every 30 min (Regular Activity Breaks). Flow mediated dilation (FMD) was measured in the popliteal artery at baseline and 6 h. Popliteal artery hemodynamics, and postprandial plasma glucose and insulin were measured over 6 h. Neither raw nor allometrically-scaled FMD showed an intervention effect (p = 0.285 and 0.159 respectively). Compared to Prolonged Sitting, Regular Activity Breaks increased blood flow (overall effect of intervention p<0.001; difference = 80%; 95% CI 34 to 125%; p = 0.001) and net shear rate (overall effect of intervention p<0.001; difference = 72%; 95% CI 30 to 114%; p = 0.001) at 60 min. These differences were then maintained for the entire 6 h. Prolonged Standing increased blood flow at 60 min only (overall effect of intervention p<0.001; difference = 62%; 95% CI 28 to 97%; p = 0.001). Regular Activity Breaks decreased insulin incremental area under the curve (iAUC) when compared to both Prolonged Sitting (overall effect of intervention P = 0.001; difference = 28%; 95% CI 14 to 38%; p<0.01) and Prolonged Standing (difference = 19%; 95% CI 4 to 32%, p = 0.015). There was no intervention effect on glucose iAUC or total AUC (p = 0.254 and 0.450, respectively). In normal-weight participants, Regular Activity Breaks induce increases in blood flow, shear stress and improvements in postprandial metabolism that are associated with beneficial adaptations. Physical activity and sedentary behaviour messages should perhaps focus more on the importance of frequent movement rather than simply replacing sitting with standing.

Co-Production at Work: The Process of Breaking Up Sitting Time to Improve Cardiovascular Health. A Pilot Study

“…Moreover, it was repeatedly highlighted that not only the intervention needed to prevent distraction from work, but employer and management endorsement and engagement was important in relation to changing perspectives of social normality and employee engagement in the intervention. Lastly, during the focus group discussion, it was evident that an intervention focusing on half-hourly breaks, where a bulk of the breaking up sitting time laboratory studies are focused [ 14 , 35 , 55 , 56 ], would be unfeasible due to the frequency of the disruption to work tasks and meetings often lasting an hour. Therefore, an hourly break strategy was implemented as a result of the compromise between the stakeholder input and researchers’ evidence-focused approach.…”

“…Similarly, Graves et al (2015) reported that eight weeks of sit–stand implementation led to a decline in total cholesterol, but not plasma glucose or plasma triglycerides, nor systolic or diastolic blood pressure [ 34 ]. Consequently, interventions which result in greater increases in physical activity and yet remain feasible are required [ 35 ].…”

Learning From Human Responses to Deconditioning Environments: Improved Understanding of the “Use It or Lose It” Principle

“…Risks associated with sedentary behavior can likely be mitigated by exercise (Tersa-Miralles et al, 2020 ; Farrahi et al, 2021 ; Gillen et al, 2021 ; Hatamoto et al, 2021 ; Peddie et al, 2021 ; Taylor et al, 2021 ), changing the behavior to breakup periods of sedentary behavior (Gouldrup and Ma, 2021 ), but certainly, as such behavior becomes more chronic and sustained, there is a risk for epigenetic alterations to the adaptations to inactivity that may pose risks for the reversibility and impact on conditions associated with aging and the impact of exercise (discussed in Barrons-Cabrera et al, 2019 ; Bagley et al, 2020 ; Rezus et al, 2020 ; Sellami et al, 2021 ). For many individuals, physical activity across the lifespan can likely impact the consequences of sedentary behavior and/or aging, possibly via the epigenetic influences of exercise or physical activity (Ling and Ronn, 2014 ).…”

The Acute Effects of Prolonged Uninterrupted Sitting on Vascular Function: A Systematic Review and Meta-analysis

“…All included studies were classified as low risk of bias for selective report. Only five studies provided details regarding allocation concealment (7,21,40,48,54). Most studies, except two studies (21,40), did not report any form of blinding.…”

“…18,37,48,49), overweight or obese (n = 19)(7), or type 2 diabetic (n = 21) (54). Sample sizes were <20, except Taylor et al (2020)(54), and most included participants were male (n = 73).…”