Autonomic Modulation After an Acute Bout of Bench Press With and Without Blood Flow Restriction

Abstract

Traditional resistance exercise may decrease vagal tone up to 30 minutes, which may increase the risk of cardiovascular events. However, the effects of resistance exercise with blood flow restriction (BFR) on autonomic modulation are unclear. PURPOSE: To evaluate autonomic modulation after resistance exercise with and without BFR in active men. METHODS: Sixteen resistance-trained men volunteered for the study. Autonomic modulation was assessed at rest, 15 (Rec1), and 25 (Rec2) minutes after three different conditions. The low-intensity bench press with BFR (LI-BFR) consisted of 4 sets of 30, 15, 15, and 15 repetitions at 30% 1-repetition maximum (1RM) with 30 second rest between sets. The traditional high-intensity bench press (HI) consisted of 4 sets of 8 repetitions at 70% 1RM with 60 seconds rest between sets, and control (CON) consisted of supine rest. Autonomic modulation was expressed as natural logarithm (Ln), and included total power (LnTP), high-frequency power (LnHF), low-frequency power (LnLF), and sympathovagal balance (LnLF/LnHF ratio). A repeated measures ANOVA was used to evaluate conditions (LI-BFR, HI and CON) across time (Rest, Rec1, and Rec2) on autonomic modulation. RESULTS: There was a significant condition by time interaction for LnTP (LI-BFR: Rest: 8.6±0.9%, Rec1: 7.9±1.0%, Rec2: 7.9±1.2%; HI: Rest: 8.6±1.6%; Rec1: 7.7±0.9%, Rec2: 7.3±1.0%; CON: Rest: 8.7± 0.8%, Rec1: 8.7±0.7%, Rec2: 8.5±0.8%, p<0.05), LnHF (LI-BFR: Rest: 7.3±1.1%, Rec1: 5.5±1.2%, Rec2: 6.6±1.5%; HI: Rest: 7.4±1.2%; Rec1: 5.9±1.4%, Rec2: 6.5±1.5%; CON: Rest: 7.5±1.1%, Rec1: 7.5±1.8%, Rec2: 7.4±1.3%, p<0.05), and LnLF (LI-BFR: Rest: 7.3±0.9%, Rec1: 5.9±0.9%, Rec2: 6.5±1.2%; HI: Rest: 7.3±1.1%; Rec1: 6.4±0.8%, Rec2: 6.6±1.2%; CON: Rest: 7.1±1.0%, Rec1: 7.1±1.8%, Rec2: 7.1±1.0%, p<0.05) such that they were reduced at Rec1 and Rec2 after LI-BFR and HI compared to Rest and CON. There was a significant (p<0.05) of time effect for LnLF/LnHF ratio (Rest: 1.0±0.1%; Rec1: 1.0±0.2%; Rec2: 1.0±0.1%) such that it was increased at Rec1 and Rec2 compared to Rest. CONCLUSIONS: These data suggest that LI-BFR and HI significantly alters autonomic modulation for at least 30 minutes, with no difference between LI-BFR and HI. Funded by School of Health Sciences at Kent State University