The Cardiovascular and Perceptual Response to Very Low Load Blood Flow Restricted Exercise

This study sought to compare cardiovascular and perceptual responses to blood flow restriction (BFR) exercise using various pressure and load combinations. Fourteen participants completed four sets of BFR elbow flexion using 10, 15 and 20% 1RM with 40 and 80% arterial occlusion pressure (AOP). AOP was measured before and after exercise. Perceived exertion (RPE) and discomfort were assessed before exercise and after each set. Data presented as mean (95% CI), except for RPE and discomfort: 25^th, 50^th, 75^th percentiles. AOP increased post-exercise (p<0.001) with larger magnitudes seen when increasing load and pressure (p<0.001) [e. g., 10/40 ΔAOP: 21 (10, 32) mmHg vs. 20/80 ΔAOP: 62 (45, 78) mmHg], which also augmented RPE (p<0.001) [e. g., 4th set 10/40: (7, 8.5, 12) vs. 4th set 20/80: (12.75, 15.5, 17.25)] and discomfort (p<0.001) [e. g., 4^th set 10/40: (0.75, 2, 4.25) vs. 4^th set 20/80: (4.25, 6, 8,)]. Volume increased via greater loads (p<0.001), and participants only reached failure during 20% 1RM conditions [20/40: 74 (74, 75) repetitions; 20/80: 71 (68, 75) repetitions]. When performing BFR exercise with very low loads the magnitudes of the cardiovascular and perceptual responses are augmented by increasing the load and by applying a higher relative pressure.