title: Impact of leg blood flow restriction during walking on central arterial hemodynamics.
abstract: Walking exercise with limb blood flow restriction (BFR) has been shown to increase muscular mass and strength even if it is performed at low exercise intensities. Despite mounting evidence for its efficacy and the increasing popularity, the safety of BFR exercise in relation to cardiac loads has not been established. The aim of this study was to determine the response of central hemodynamics during the BFR exercise to assess its impact on cardiac load. Fifteen apparently healthy sedentary or recreationally active adults (10 men and 5 women, 27 ± 1 yr) underwent five bouts of 2-min constant treadmill walking at 2 mph with 1-min rest intervals either with or without BFR on both proximal thighs. Beat-by-beat blood pressure and hemodynamics (via Modelflow method) were measured, and central arterial hemodynamics were evaluated with pulse wave analyses via general transfer function. Incident wave amplitude (IWA) and reflected wave amplitude (RWA) were obtained by the wave separation analysis. Peripheral systolic blood pressure (SBP) increased more substantially during walking with BFR (43 ± 5% vs. baseline) than without BFR (11 ± 4% vs. baseline). Aortic SBP did not change significantly during walking without BFR, but there was a substantial elevation in aortic SBP (43 ± 5% vs. baseline) during walking with BFR. Significant effect of BFR was seen in IWA but not in RWA. These findings suggest that even during slow-speed walking, leg BFR induces substantial hypertensive responses in the aorta. However, this response could not be explained by the augmented wave reflection.
authors.affiliation: Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan; jun.sugawara@aist.go.jp.
authors.forename: Jun
authors.initials: J
authors.lastname: Sugawara
authors.affiliation: Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; and.
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Tomoto
authors.affiliation: Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D001011:Aorta / Q000502:physiology; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D005385:Fingers / Q000098:blood supply; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D006973:Hypertension; D007866:Leg / Q000098:blood supply*; D008297:Male; D010865:Pilot Projects; D063177:Pulse Wave Analysis; D012039:Regional Blood Flow / Q000502:physiology*; D055070:Resistance Training; D014111:Tourniquets; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: aortic blood pressure; pulse wave analysis; tourniquet