Effect of Cuff Pressure on Blood Flow during Blood Flow–restricted Rest and Exercise

Abstract

The purpose of this study was to investigate the blood flow/pressure relationship (linear or nonlinear) in the superficial femoral artery when seated, as well as to investigate blood flow changes with exercise using varying cuff pressures and a preexercise (PE) condition. The presence of venous outflow with occlusion at rest and exercise was also investigated. Methods: Twenty-three subjects visited the lab on 3 occasions. First to determine linearity of blood flow using 0% to 90% arterial occlusion pressure (AOP), and venous outflow at rest and during exercise with cuff inflated to 40% AOP. Subsequent visits compared blood flow between rest and PE conditions to determine average blood flow, heart rate, systolic and diastolic blood pressure changes in response to a blood flow-restricted (BFR) exercise protocol. Results: Blood flow/pressure relationship is nonlinear at the superficial femoral artery (p < 0.01). No significant differences in average blood flow, conductance or mean arterial pressure (MAP) were found between 30% to 80% AOP (p = 1.0 to .08). Blood flow is not significantly different between rest and PE groups (p = 0.49) although initial 40% AOP and 40% exercise arterial occlusion pressure (EAOP) values were different between rest and PE groups. (p < 0.01). Conclusion: The nonlinear relationship at the superficial femoral artery demonstrates higher cuff pressures are not necessary to reduce blood flow in BFR exercise of the lower extremity. Furthermore, PE or warm-up is not necessary prior to determining EAOP as it does not alter blood flow responses during BFR exercise. We found evidence of venous outflow above the cuff both at rest and during exercise at 40% AOP.

Acute physiological and perceptual responses to moderate intensity cycling with different levels of blood flow restriction

“…In the former study, as the external pressure applied on the thigh increased from 0% to 100% of occlusion pressure, blood flow and mean blood velocity in the posterior tibial artery decreased in a linear manner [ 26 ]. In contrast, Crossley et al [ 28 ] reported a non-linear decline in muscle blood flow characterized by an abrupt rate of decline in muscle blood flow as the occlusion pressure increased from 80% to 100%. One point relevant to our study is that, to our best knowledge, no data exist on the relationship between different levels of occlusion pressure and muscle blood flow while exercising with relatively large muscle groups.…”

“…The similarity in TSI decline between MI-BFR and HI may indicate a similar level of muscle hypoxia between the two conditions despite the fact that exercise intensity is much lower in the former (40% P peak ) compared to the latter (70% P peak ). Previous studies have shown a decline in muscle blood flow as a result of external pressure application [ 26 , 28 ]. In the former study, as the external pressure applied on the thigh increased from 0% to 100% of occlusion pressure, blood flow and mean blood velocity in the posterior tibial artery decreased in a linear manner [ 26 ].…”

“…Ours is one of the very few studies showing this effect when exercising at submaximal intensity with a large pressure scale and a large muscle mass. Previous studies have used small muscle mass exercise tasks such as plantar flexion and knee extension [ 27 , 28 ]. In the latter study, an occlusion pressure of 40% provided an ischemic stimulus comparable to that of 80% occlusion pressure during plantar flexion [ 28 ].…”

“…Research suggests that muscular blood flow is relatively constant in the range of 40% to 90% of arterial occlusion pressure [ 26 ]. However, acute studies are either at rest [ 25 , 27 ] or during exercise with small muscle groups [ 28 ]. Among the studies involving exercise at submaximal intensities with large muscle mass such as running [ 15 ] and cycling [ 16 – 18 ] only one has employed different levels of occlusion pressure, which are 40% and 60% AOP [ 16 ].…”

“…Exercising with a large muscle mass will increase blood pressure for the same relative intensity, and this may affect blood flow in the working muscles [ 24 , 28 ]. Based on the equation of blood flow (blood flow = mean arterial pressure (MAP) / total peripheral resistance), it is assumed that any increase in MAP will affect blood flow.…”