Effect of physical activity breaks during prolonged sitting on vascular outcomes: A scoping review

Abstract

Emerging evidence claims the vascular benefits of varied frequency and duration of physical activity (PA) breaks, whereas the efficacy of varied intensity remains unexplored. We aimed to collate and summate the studies investigating the PA breaks at various intensities on vascular protection. Seven electronic databases were searched for potential studies till Jan 31, 2022. The eligible studies should have administered PA breaks of differing intensities in prolonged sitting postures and explored regional vascular changes [flow mediated dilation (FMD), shear stress, diameter, and blood flow] using ultrasound and novel outcome markers. Two independent reviewers assessed the studies for eligibility after abstract and full-text screen, and appropriate data were extracted to summarise vascular protective effects with PA breaks. Our findings reveal adverse regional vascular outcomes with prolonged sitting (FMD ≈ -1.5%, diameter ≈ -0.06 mm), whereas PA breaks of any intensity were found to improve endothelial functions (FMD ≈ +0.5%, diameter ≈ +0.1 mm, shear ≈ +13 s^-1) and mitigate the adverse effects associated with prolonged sitting. Compared with high-intensity activity, low-intensity PA breaks alleviate arterial stiffness and endothelial dysfunction risks.

Keywords: Duplex ultrasound; endothelial function; physical activity breaks; pulse velocity; sedentary lifestyle; shear stress.

Figure 1

PRISMA flowchart demonstrating the inclusion and exclusion of the studies in the review

Figure 2

Measures used to quantify the vascular functions in the included studies

Figure 3

Infographics show the plausible physiological and mechanistic pathways underpinning the vascular effects of prolonged sitting and their interruptions