The Effects Of Venous Pooling During Prolonged Sitting On Central Arterial Stiffness

Abstract

PURPOSE: Higher arterial stiffness (AS) is associated with increased cardiovascular disease (CVD) risk. During prolonged sitting (PS), AS increases. However, the mechanism for increased AS during PS has not been elucidated. One plausible mechanism is lower-extremity venous pooling (VP), which would subsequently reduce venous return and aortic shear stress. The aim of this study is to determine the effect of venous pooling manipulation on central AS. In order to more fully understand how AS increases during PS, pulse wave velocity, the “gold standard” non-invasive arterial stiffness measurement, was used to measure AS. In order to more fully understand CVD risk, it is important to see if there is relationship between PS and AS. METHODS: Nine participants were part of a randomized crossover trial, where they were assigned to one of two groups: a group who had a bilateral tourniquet applied bilaterally to their legs to induce VP (CUFF) and a control group who did not wear a bilateral tourniquet (NON-CUFF). The participant then sat in a standard chair for 120 minutes. VP was measured the change in calf circumference. Linear mixed models were used to compare the bfPWV values over time and across conditions. RESULTS: The calf circumference measurements increased by 3.69% for the CUFF condition and increased by 0.25% for the NON-CUFF condition. There was no interaction effect in this study. The main effect for time was non-significant for bfPWV (p=0.249, ß = 0.453 m/s). The main effect for condition was trending toward significance, but non-significant (p=0.069,ß = 0.273 m/s). One participant was not included because the participant suffered a vasovagal episode. CONCLUSIONS: While no significant results were found, this preliminary data resulted in a non-significant, condition effect (p=0.069, ß = 0.273 m/s) that trended toward significance. These preliminary data may show more statistically significant results when tested in a full-scale trial, with greater participant count. This is something that can be used as pilot data, and can be further investigated in future and on-going studies. If an increase in bfPWV is found, treatments targeting VP could be used to affect bfPWV outcome.