Acute cardiovascular responses to resistance training with and without blood flow restriction in healthy individuals

Introduction: Blood flow restriction exercise has proven to be an effective training method to promote neuromuscular adaptations, however, a consensus about the effect on other physiological and safety variables, such as cardiovascular responses, has yet to be reached. Purpose: The aim of this study was to compare the acute cardiovascular responses during and after three different resistance training protocols. Material & methods: Fifty-two participants (27.3±7 years; 177.6±11 cm; 72.2±13.7 kg) were randomly allocated into three groups: low-intensity exercise without (LI, n=13) and with blood flow restriction (LI-BFR, n=24), and high-intensity exercise (HI, n=15). Participants from LI and LI-BFR groups performed four sets (1x30 + 3x15 reps) at 30% 1RM, while HI group performed four sets (1x30 with 30% 1RM + 3x10 reps with 75% 1RM) of dominant-side plantar flexion exercise. For LI-BFR group, a cuff was placed under popliteal region and inflated at 30% of the individual´s occlusion pressure (47.6 ± 19.8 mmHg). Results: Blood pressure (BP), heart rate (HR) and oxygen saturation (SpO2) were assessed at baseline, after each set and post-exercise. HR increases significantly during exercise across all protocols, with greater increases for HI group after 4th set (p<0.001; G=1.072) but without differences between groups. HI and LI-BFR protocols showed higher significant post-exercise hypotension and greater reduction in MAP (p<0.05) than LI group. RPP during exercise was different from HI to LI and LI-BFR (p<0.05). HI protocol reduced SpO2 during all sets of exercise (p<0.05). Conclusions: The results of this study indicate that LI-BFR promotes similar hypotensive response to HI, with equal or lower cardiovascular responses during exercise than traditional resistance training.