Effect of Acute Grape Seed Extract Supplementation on the Heart Rate Recovery in Young Individuals

Evidence suggests postexercise heart rate recovery (PHRR) is a useful tool in evaluating cardiac autonomic function. Altered cardiac autonomic function is characterized by heightened sympathetic nervous system and abnormal reactivation of the parasympathetic nervous system and is associated with delayed PHRR. Although grape seed extract (GSE) supplementation has been shown to increase nitric oxide production, there is limited evidence on its potential beneficial effects on PHRR. This study hypothesized that GSE would be effective in reducing total peripheral resistance and blood pressure (BP), and in improving heart rate recovery kinetics in young individuals. Purpose: The aim of this study was to investigate the effect of GSE supplementation on PHRR during increased sympathetic activity induced by muscle metaboreflex activation (MMA) in young individuals. Methods: Twelve healthy males (22.2±1 years, BMI: 24.3±1 kg/m 2 , screening BP: 102±3/65±3 mmHg) were randomly assigned via a double-blind, cross-over design to either receive GSE (300mg, 2 capsules) or placebo (PL; 300mg, 2 capsules) with a washout period of at least 72 hrs. between trials. A submaximal exercise test was performed using a cycle ergometer combined with isometric handgrip exercise using a handgrip dynamometer, and blood flow occlusion by placing a cuff over the brachial artery of the dominant arm. PHRR was measured at 5 sec. intervals throughout the experiment. The PHRR was evaluated between GSE and PL at every min. for 300 sec. Results: PHRR kinetics significantly improved following GSE supplementation (74.3±7.5 sec) compared to PL condition (86.2±10.4 sec) ( P = 0.034). MAP increased from resting (76±2 mmHg) to exercise (82±3 mmHg) during circulatory occlusion after isometric handgrip exercise ( P = 0.016), confirming that MMA increased sympathetic output. Conclusion: Our results suggest that GSE is effective in improving heart rate recovery kinetics during heightened sympathetic activity induced by MMA in young individuals. Thus, regular treatment with GSE can provide a nonpharmacological intervention to reduce sympathetic hyperactivity in conditions where excessive sympathetic activity is consistently present. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.