Cardiorespiratory And Metabolic Responses To Blood-flow Restricted Running In Female Distance Runners

Low-intensity (LI) aerobic exercise with blood-flow restriction (BFR) increases heart rate (HR), oxygen consumption (VO2), and ratings of perceived exertion (RPE), sometimes to similar levels as high-intensity (HI) exercise. Distance runners may benefit from LI-BFR running in periods of reduced volume or intensity, perhaps due to injury, but first, the acute cardiorespiratory, metabolic, and perceptual responses should be evaluated. PURPOSE: To compare HR, VO2, blood lactate (BLa), and RPE during LI-BFR running and HI running. METHODS: Fifteen female distance runners (age 23 + 4 yrs, height 1.67 + 0.50 m, body mass 57.6 + 5.7 kg, VO2max 51.0 + 4.5 mL•kg-1•min-1) completed three randomized 12-minute running conditions: LI control (40% VO2max), HI (80% VO2max), and LI-BFR (40% VO2max). VO2, HR, and RPE were measured at rest, and every 3-minutes. BLa was measured at rest, immediately-post (ImmPost), and 3-minutes post-exercise (3minPost). RESULTS: VO2 remained steady in each condition (p = 0.075, ηp2 = 0.155), but average VO2 differed between the conditions (p < 0.001), as HI (39.4 + 3.9 mL•kg-1•min-1) was greater than LI-BFR (25.3 + 2.6 mL•kg-1•min-1) and both were higher than LI (22.5 + 3.1 mL•kg-1•min-1). HR differed between the 3 conditions (p < 0.001, ηp2 = 0.745) and averaged 166 + 8 bpm, 142 + 13 bpm, and 124 + 11 bpm for HI, LI-BFR, and LI, respectively. BLa was similar in HI and LI-BFR conditions ImmPost and 3minPost (p > 0.05), and both were higher than LI (p < 0.017). RPE in the HI (11 + 2) and LI-BFR (12 + 2) conditions were similar (p = 0.236), while LI (9 + 1) was lower (p < 0.001). CONCLUSION: HI running elicits greater VO2 and HR responses than LI-BFR running, suggesting that HI running would result in more robust long-term training responses. However, if one cannot engage in HI running because of injury and rehabilitation, LI-BFR running could be a feasible and temporary alternative to HI running. University of New Hampshire Hamel Center for Undergraduate Research: Summer Undergraduate Research Fellowship Grant