Effects of acute grape seed extract supplementation on muscle metaboreflex in healthy young individuals

Objectives Limited data have reported regarding the effects of grape seed extract (GSE) on blood pressure (BP) to increased sympathetic activity induced by the muscle metaboreflex (MMR) activation. Accordingly, this study aimed to determine whether GSE supplementation could reduce the BP in response to static handgrip exercise (SHE) and post-exercise muscular ischemia (PEMI) in normotensive young adults. Methods In 12 healthy subjects (7 male and 5 female, 24.6 ± 3.4 yr), we compared acute effect of both GSE and placebo (PL) on changes from rest in mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) during SHE and PEMI. Subjects completed 2 min of SHE at 30% of maximal voluntary contraction (MVC) followed by 2 min of PEMI. Results MAP was significantly increased during SHE and MMR in both conditions, but the rise was significantly attenuated following GSE supplementation compared to PL supplementation (20 ± 2 mmHg vs. 25 ± 2 mmHg). CO was significantly increased during SHE and MMR in both conditions, but the rise was significantly higher in GSE treatment than PL treatment. TPR was significantly increased in both conditions, but the rise was significantly higher following PL treatment compared to GSE treatment (SHE: 3.1±0.5 mmHg/L/min vs. 0.9 ± 0.6 mmHg/L/min; MMR: 2.7 ± 0.4 mmHg/L/min vs. 1.4 ± 0.4 mmHg/L/min). Conclusion This study demonstrated that dietary supplementation with GSE decreased the MMR-induced pressor response via a decrease in peripheral vasoconstriction. Our findings suggest that GSE is effective in reducing BP response mediated by MMR activation.