Effects of leg blood flow restriction during walking on cardiovascular function

Abstract

Introduction: Exercise with limb blood flow restriction (BFR) is a very popular exercise modality in Japan and is spreading widely to the rest of the world. The underlying principle of this training modality is that under the conditions of restricted blood flow, even low-intensity exercise can provide significant muscle strength and hypertrophy. One concern, however, is that BFR during exercise may place unnecessary burden on those with compromised cardiac function.

Methods: We determined the impact of leg BFR during walking on cardiovascular function in 17 young (26 ± 1 yr) healthy volunteers. Each subject underwent five bouts of 2-min treadmill walking at 2 miles·h(-1) with 1-min interval either with or without tourniquet cuffs inflated on both thighs.

Results: Heart rate increased more during the BFR session, whereas stroke volume decreased greater during the BFR session. Blood pressure increased significantly and substantially during the BFR session. Consequently, an increase in double product, an index of myocardial oxygen demand, was more than threefold higher in the BFR condition. Systemic arterial compliance evaluated by stroke volume/pulse pressure ratio significantly increased during the control session by 14% but reduced during the BFR condition by 19%. Popliteal artery flow-mediated vasodilation decreased significantly after the exercise with BFR but not after the control session.

Conclusions: Even at low intensity, the aerobic exercise with BFR requires a greater cardiac work and decreases endothelial function. Limb BFR during exercise may need to be more cautiously prescribed to those with compromised cardiac conditions.

Conflict of interest statement

Conflict of interest

We have no financial, consultant, institutional and other relationships that might lead to bias or a conflict of interest.

Figures

Figure 1

Changes in blood pressure in response to the exercise sessions with (closed circles) or without (open circles) leg blood flow restriction (BFR). *P

Figure 2

Changes in systemic hemodynamic variables in response to the exercise sessions with (closed circles) or without (open circles) leg blood flow restriction (BFR). Data show relative changes from the baseline (standing on the treadmill before exercise). †P

Figure 3

Changes in double product (an index of myocardial oxygen demand) and stroke volume/pulse pressure ratio (SV/PP; an index of systemic arterial compliance) to the exercise sessions with (closed circles) or without (open circles) leg blood flow restriction (BFR). Data show relative changes from the baseline (standing on the treadmill before exercise). †P

Figure 4

Popliteal artery flow-mediated vasodilation (FMD) (top) and normalized FMD with area under the curves of shear rate (bottom) before and after exercise session with or without leg blood flow restriction (BFR). Data are mean±SEM.