Cardiovascular, Perceptual and Metabolic Demands Associated with Low-intensity Blood Flow Restriction Cycling

Abstract

The use of blood flow restriction (BFR) during very-low-intensity walking can improve aerobic and anaerobic capacity; however, no research exists which has examined BFR during more ecologically valid aerobic exercise, such as intensities consistent with the American College of Sports Medicine guidelines for low- to moderate-intensity. PURPOSE: To examine the acute cardiovascular, metabolic and perceptual responses to aerobic BFR exercise at intensities consistent with the American College of Sports Medicine guidelines. METHODS: Eighteen healthy males (23 ± 3 y) completed, in a randomized and counterbalanced order, low-intensity (LI), low-intensity with BFR (LIBFR) and high-intensity (HI) interval cycling sessions. These included a standardized warm-up and three 2-min intervals with 2-min of recovery cycling (10W) between efforts. During HI, LI and LIBFR sessions efforts were set to 85%, 40% and 40% of peak power, respectively. During LIBFR, 80% arterial occlusion was applied to both legs during the efforts and removed during recovery. Continuous measures of heart rate (HR), cardiac output (CO) and oxygen consumption (V[Combining Dot Above]O2) were recorded. Blood pressure and rating of perceived exertion (RPE) were measured at the end of each interval. Lactate was measured pre- and post-session. RESULTS: Blood pressure, HR, CO, V[Combining Dot Above]O2, lactate and RPE were greatest during HI (range; p=0.01 to p=0.04). During the intervals, blood pressure, HR and CO were greater during LIBFR compared with LI (range; p=0.01 to p=0.04). V[Combining Dot Above]O2 measured during the recovery periods were greater in LIBFR compared with LI (p=0.01; for all time points). Post-session lactate was greater (p=0.01) during LIBFR (6.3 ± 0.49 mmol[BULLET OPERATOR]L−1) compared with LI (2.8 ± 0.29 mmol[BULLET OPERATOR]L−1). Importantly, mean arterial pressure during the third interval (124.2 ± 2.3 mmHg vs. 113.9 ± 2.5 mmHg) was greater (p=0.01) in LIBFR compared with HI. CONCLUSION: LIBFR results in greater cardiovascular and metabolic stress compared with LI alone, and therefore could provide an alternative modality to increase aerobic fitness for individuals not able to perform exercise at high-intensity. However, LIBFR may not be suitable for all populations, specifically those with vascular dysfunction.