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

In this study, our objective was to investigate the impact of varying intensity levels of breaks from physical activity (PA) on vascular health. Prior research has shown that taking breaks from PA can have positive effects on vascular health, but the role of different intensity levels remained unexplored. To address this, we conducted a comprehensive review of studies from seven electronic databases until January 31, 2022. The selected studies administered PA breaks of different intensities during prolonged sitting and assessed changes in regional vascular health using ultrasound and novel outcome markers such as flow mediated dilation (FMD), shear stress, diameter, and blood flow. After careful assessment by independent reviewers, we found that prolonged sitting was associated with adverse regional vascular outcomes, including reduced FMD (approximately -1.5%) and diameter (approximately -0.06 mm). However, any intensity level of PA breaks was found to improve endothelial functions, with positive changes observed in FMD (approximately +0.5%), diameter (approximately +0.1 mm), and shear stress (approximately +13 s-1). These findings suggest that low-intensity PA breaks may be more effective in mitigating the risks of arterial stiffness and endothelial dysfunction when compared to high-intensity activities.