Effects Of Modifying Arterial Compliance On Measures Of Arterial Occlusion Pressure In Blood Flow Restriction

We reported last year that pulse wave velocity (PWV), an indicator of arterial compliance, statistically significantly explained a portion of the variance in arterial occlusion pressure (AOP), the minimum pressure required to completely occlude blood flow to a limb. Invoking acute changes in arterial compliance may impact the measurement of AOP. PURPOSE: To determine whether a protocol shown to increase arterial compliance has an effect on AOP. METHODS: Sixty-three (men = 30) participants visited the laboratory on one occasion. Participants were randomized in a counterbalanced manner into either intervention or time-matched control groups. Following anthropometric measurements, blood pressure was recorded after 15 minutes of supine rest. Resting AOP in the arm was measured using a 5 cm wide inelastic cuff and vascular doppler. Participants in the control group rested supine for an additional 10 minutes, while those in the intervention group received 6 sets of 12 inflation/deflation cycles in the arm at 100% of AOP, 4 seconds inflated and 2 seconds deflated, with 30 seconds of rest between sets. This protocol has been shown to increase arterial compliance. AOP was measured again following either intervention or control rest. Data was analyzed using repeated-measures (group by time) ANOVA. Statistical significance was set a priori at α = .05. RESULTS: All 63 participants completed the study (mean(SD): age: 21(2.2) yrs; height: 1.71(.08) m; body mass: 78.1(18.1) kg). There was no statistically significant group by time interaction (P = .142). There was a statistically significant effect of time, with AOP decreasing from the first to second measure (mean(SE): pre: 161.6 (3.2) mmHg vs. post: 159.8 (3.1) mmHg, P = .001). CONCLUSIONS: Using a protocol that has been shown to increase arterial compliance, there was no statistically significant effect on the AOP measurement. It could be that the contribution of arterial compliance to AOP is small enough to not show in the acute measurement. AOP did decrease across both groups; this could indicate that the additional 10 minutes of supine rest allowed for further decreases in cardiovascular contributions to the AOP measurement. Changes in AOP were small enough to have little, if any, effect on blood flow restriction pressure prescription.