Autonomic modulation following an acute bout of bench press with and without blood flow restriction.

PURPOSE: Traditional resistance exercise decreases vagal tone up to 30 min after an acute bout of resistance exercise, which may increase the risk of cardiovascular events. However, the effects of resistance exercise with blood flow restriction (BFR) on autonomic modulation are unclear. To evaluate autonomic modulation after resistance exercise with and without BFR in resistance-trained men. METHODS: Eleven young men volunteered for the study. Autonomic modulation was assessed at rest, 15 (Rec 1), and 25 (Rec 2) minutes after low-load bench press with BFR (LL-BFR), traditional high-load bench press (HL), and a control (CON). Autonomic modulation assessments were expressed as natural logarithm (Ln), and included total power (LnTP), low-frequency power (LnLF), high-frequency power (LnHF), sympathovagal balance (LnLF/LnHF ratio), root mean square of the successive differences (LnRMSSD), and the proportion of intervals differing by > 50 ms from the preceding intervals (LnPNN50). A repeated measures ANOVA was used to evaluate conditions (LL-BFR, HL and CON) across time (Rest, Rec1, and Rec2) on autonomic modulation. RESULTS: There were significant condition by time interactions for LnTP, LnHF, and LnRMSSD such that they were reduced during recovery after LL-BFR and HL compared to Rest and CON. There were no interactions in the LnLF, LnLF/LnHF ratio, and LnPNN50. CONCLUSIONS: These data suggest that LL-BFR and HL significantly alter autonomic modulation up to 30 min after exercise with significant reduction after HL compared to LL-BFR when exercise volume is equated.

Pulse wave reflection responses to bench press with and without practical blood flow restriction.

Resistance exercise is recommended to increase muscular strength but may also increase pulse wave reflection. The effect of resistance exercise combined with practical blood flow restriction (pBFR) on pulse wave reflection is unknown. The purpose of this study was to evaluate the differences in pulse wave reflection characteristics between bench press with pBFR and traditional high-load bench press in resistance-trained men. Sixteen resistance-trained men participated in the study. Pulse wave reflection characteristics were assessed before and after low-load bench press with pBFR (LL-pBFR), traditional high-load bench press (HL), and a control (CON). A repeated-measures ANOVA was used to evaluate differences in pulse wave reflection characteristics among the conditions across time. There were significant (p ≤ 0.05) interactions for heart rate, augmentation index, augmentation index normalized at 75 bpm, augmentation pressure, time-tension index, and wasted left ventricular energy such that they were increased after LL-pBFR and HL compared with rest and CON, with no differences between LL-pBFR and HL. Aortic pulse pressure (p < 0.001) was elevated only after LL-pBFR compared with rest. In addition, there was a significant (p ≤ 0.05) interaction for aortic diastolic blood pressure (BP) such that it was decreased after LL-pBFR compared with rest and CON but not HL. The subendocardial viability ratio and diastolic pressure-time index were significantly different between LL-pBFR and HL compared with rest and CON. There were no significant interactions for brachial systolic or diastolic BP, aortic systolic BP, or time of the reflected wave. In conclusion, acute bench press resistance exercise significantly altered pulse wave reflection characteristics without differences between LL-pBFR and HL.