Author(s): MOINUDDIN, A., PATERSON, C., TURNER, L., STONE, K., LUCAS, S., GRIFFITHS, T., FRYER, S., Institution: UNIVERSITY OF GLOUCESTERSHIRE, Country: UNITED KINGDOM, Abstract-ID: 558

INTRODUCTION:
Sedentary behaviour is associated with heightened cardiovascular disease (CVD) risk 1, with increased arterial stiffness (AS) being implicated as a principal pathophysiological mechanism. Numerous studies have demonstrated that AS, determined using pulse wave velocity (PWV), can increase (worsens) during prolonged uninterrupted sitting, but this effect can be attenuated when sitting is interrupted with short bouts of activity. However, to date, there has been no consolidation of the literature to determine the effect of sitting with and without interruptions on PWV. Objectives: The current systematic review, with meta-analysis, aimed to consolidate and quantify the AS response to: (1) prolonged uninterrupted- and (2) interrupted-sitting, as assessed by central- and peripheral-PWV
METHODS:
Data Sources: Electronic databases (PubMed, Web of Science and, SPORTDiscus) were searched from inception to August 2023. Study Selection: The inclusion criteria for objective (1) were: randomised experimental trials pre- versus post-test trials; adult participants (≥18 years) who were free of any known chronic illness; prolonged sitting period of at least 1-h; assessment of any segmental measure of PWV; PWV was assessed pre- and post-sitting in the same posture. Additional inclusion criteria for objective (2) were: if a strategy was employed to disrupt the effects of sitting, the strategy must have been during the sitting period; there must have been a control (uninterrupted sitting) group or condition, and the interruption strategy must have involved the participants actively moving their limbs. Appraisal and Synthesis Methods: In total, 326 articles were identified, of which 10 and 6 met inclusion criteria for objectives: (1) and (2), respectively. Mean differences (MD) and 95% confidence intervals (CI) were calculated for all trials using a three-level random-effects model, with restricted maximum likelihood (REML) estimation. The amount of heterogeneity was estimated using Cochran’s Q, and Higgins I2 tests.
RESULTS:
(1) Prolonged uninterrupted sitting resulted in a significant increase in cf-PWV (MD = 0.211 mꞏs, 95% CI = 0.136 to 0.285, p < 0.0001). (2) Interrupting bouts of prolonged sitting resulted in a significant increase in cf-PWV (MD = 0.145 mꞏs, 95% CI = 0.056 to 0.235, p < 0.0014), that was lower compared to the uninterrupted sitting.
CONCLUSION:
This is the first known study to assess the pooled effect of prolonged sitting (with and without interruption) on arterial stiffness (PWV). Uninterrupted sitting appears to significantly increase (worsen) arterial stiffness (cf-PWV), and interrupting sitting with bouts activity may confer some protective effect, but it does not remove it entirely. Our conclusions are strengthened by our robust meta-analytic model, 3-hours (median) sitting period, and prominent female representation (~50%).
Ref: 1. Matthews CE, et al. Amount of time spent in sedentary behaviors and cause-specific mortality in US adults. Am J Clin Nutr. (2012) 95:437–45