Acute Effects of Autoregulated and Non-autoregulated Blood Flow Restrictive Exercise on Indices of Arterial Stiffness

To investigate the acute effects of autoregulated (AR) and non-autoregulated (NAR) BFR exercise on indices of arterial stiffness. AR BFR training devices adjust pressure in the cuff ensuring similar pressure throughout the range of motion when the muscles are contracted (dilatated) and relaxed. NAR BFR training devices do not adjust pressure in the cuff throughout the range of motion when the muscles are contracted and relaxed which cause greater pressures at different points in the range of motion. METHODS: Following a randomized AR or NAR familiarization training session, 20 adults (23±5 years; 7 female) participated in 3 randomized treatment-order sessions with AR-BFR, NAR-BFR, and no- BFR separated by 1-week washout periods. Participants performed 4 sets of dumbbell wall squats to failure using 20% of 1 repetition maximum (1-RM) at 2-second concentric/eccentric cadence. Training limb occlusion pressure (LOP) was set at 60% of supine LOP for both the AT and NAR sessions. Testing before and immediately following the training session included ultrasonography of the carotid artery, applanation tonometry, and blood pressure acquisition. Two-way ANOVAs were used to examine the effects of treatment and the treatment-order interaction on pulse wave velocity (PWV), beta-stiffness index (β-stiff), and arterial compliance (AC). RESULTS: There were no baseline differences in CF- (carotid-femoral) PWV, CR- (carotid-radial) PWV, β-stiff, and AC (all p > 0.05). CF-PWV increased in the NAR-BFR (mean difference = 0.57±1.12 m/s, p = 0.02) and no-BFR (mean difference = 0.63±1.42 m/s, p = 0.03) groups following the exercise session. CR-PWV increased in the no-BFR (mean difference = 0.82±1.5 m/s, p = 0.03) group. And there was an interaction effect in CFPWV between AR-BFR and NAR-BFR (mean difference = 0.70±1.6 m/s, p = 0.03). CONCLUSION: These findings show acute AR-BFR training does not influence indices of arterial stiffness while acute NAR-BRF training increases central stiffness.