Effects of Breaking Up Prolonged Sitting on Cardiovascular Parameters: A systematic Review.

The aim of this systematic review was to analyze the acute and chronic effects of sitting breaks on cardiovascular parameters. PubMed and Web of Science databases were searched by two independent researchers for relevant studies published until February 2020. Acute or chronic studies reporting the effects of sitting breaks or reduction in sitting time on cardiovascular parameters were examined. The eligibility criteria followed PICOS: Population - Humans ≥ 18 years old; Interventions - Sitting break strategies; Comparisons - Uninterrupted sitting; Outcomes - Cardiovascular parameters (blood pressure, heart rate, ambulatory blood pressure, vascular function, pulse-wave velocity, cerebral blood flow and biomarkers); Study design - Randomized controlled trials, non-randomized non-controlled trials and randomized crossover trials. Forty-five studies were included, where 35 investigated the acute and 10 the chronic effects of sitting breaks or reductions in sitting time. Walking was the main acute study strategy, used in different volumes (1 min 30 s to 30 min), intensities (light to vigorous) and frequencies (every 20 min to every 2 h). Acute studies found improvements on cardiovascular parameters, especially blood pressure, flow-mediated dilation, and biomarkers, whereas chronic studies found improvements mostly on blood pressure. Breaking up or reducing sitting time improves cardiovascular parameters, especially with walking.

Are Vascular Parameters Associated with Walking Impairment in Patients with Claudication?

BACKGROUND: The mechanisms underlying functional impairments in symptomatic PAD patients are controversial and poorly understood. Endothelial dysfunction and arterial stiffness have been proposed as potential mechanisms related to functional impairment in symptomatic PAD patients, however, more studies are needed to confirm these associations. OBJECTIVE: To analyze the association between vascular function and walking impairment in patients with peripheral arterial disease (PAD) and symptoms of claudication. METHODS: This was a cross-sectional study that included 68 patients with symptomatic PAD. All patients underwent an objective (Six-minute walk test [6MWT], 4-meter walk test) and a subjective (Walking Impairment Questionnaire [WIQ]) measurement of walking impairment. Vascular parameters measured were pulse-wave velocity (PWV) and flow-mediated dilation (FMD). Multiple linear regression was performed to investigate the association among walking impairment variables with vascular function parameters. RESULTS: No significant associations between the claudication onset distance (PWV: b=.060, P = 0.842; FMD: b=-.192, P = 0.456), 6MWT (PWV: b=.007, P = 0..975; FMD: b=.090, P = 0.725), WIQ distance (PWV: b=.337, P = 0.117; FMD: b=-.025, P = 0.895) WIQ speed (PWV: b=.320, P = 0.181; FMD: b=-.028, P = 0.497), WIQ stairs (PWV: b=.256, P = 0.204; FMD: b=-.228, P = 0.230), 4-meter usual walk (PWV: b=-.421, P = 0.107; FMD: b=-.338, P = 0.112), 4-meter fast walk (PWV: b=-.496, P = 0.063; FMD: b=-.371, P = 0.086) and vascular function were found. CONCLUSIONS: In symptomatic PAD patients, vascular function is not associated to walking impairment, even when adjusting for comorbid conditions and diabetes.