Hemodynamic and Cerebrovascular Responses to an Acute Bout of Blood Flow Restriction Resistance Exercise

Blood flow restriction (BFR) training is a novel exercise modality characterized by restricting blood flow to active muscles by the use of an occlusive device. A hallmark of this training is the use of lighter loads, making it a potentially valuable tool for patients exercising in a rehabilitative setting. Despite growing interest in BFR training, no investigation has assessed the combined hemodynamic and cerebrovascular responses to this exercise modality. One concern about application of BFR exercise to the rehabilitation setting is the potential for an amplification of the exercise pressor reflex (EPR), which could cause an unsafe rise in arterial blood pressure. The aim of this investigation was to compare the hemodynamic and cerebrovascular responses between BFR resistance exercise and traditional resistance exercise (TE). We hypothesized that the exercise-induced elevation in arterial pressure and cerebral blood flow would be attenuated with BFR, due to the use of lower workloads. Five healthy human volunteers (3M/2F; age, 25.4±1.1 years) performed 3 sets of 10 repetitions of leg press with (BFR) or without (TE) BFR (220 mmHg), separated by 1-min rest periods. BFR was performed at 20% of 1 repetition maximum (1RM) while TE was performed at 65% of 1RM. Heart rate (HR) and arterial pressures were collected via ECG and finger photoplethysmography. Middle cerebral artery blood velocity (MCAv) was measured via transcranial Doppler ultrasound, and oxygen saturation of the frontal cortex (ScO2) was measured via near-infrared spectroscopy. Rate pressure product (RPP) was calculated as systolic arterial pressure multiplied by HR, and used as an index of myocardial oxygen demand. Mean arterial pressure (MAP) and RPP were both higher during TE compared with BFR during sets 2 and 3 (MAP: TE, 116±10 mmHg vs. BFR, 104±6 mmHg for BFR, P=0.05 (Set 3); RPP: TE, 16229±2387 mmHgbpm vs. BFR, 11889±978 mmHgbpm, P≤0.02 (Set 3)). While MCAv and ScO2 increased with exercise (P