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

Evidence has suggested that post-exercise heart rate recovery (PHRR) is a useful tool in evaluating cardiac autonomic function. Altered cardiac autonomic function is characterized by heightened sympathetic activation and the abnormal reactivation of the parasympathetic nervous system and is associated with delayed HRR. Although grape seed extract (GSE) supplementation has been shown to increase nitric oxide production and modify sympathetic output, there is limited evidence on its potential beneficial effects on PHRR. We investigated the effect of GSE supplementation on PHRR during sympathetic overactivation induced by muscle metaboreflex activation (MMA) in young individuals. Participants were randomly assigned, via a double-blind, cross-over design, to either receive GSE (300 mg, two capsules) or PL (300 mg, two capsules), with a washout period of at least 72 h. between trials. A submaximal exercise test was performed using a cycle ergometer combined with an 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 s. intervals throughout the experiment. The PHRR was evaluated between GSE and PL at every min. for 300 s. PHRR kinetics significantly improved following GSE supplementation (74.3 ± 7.5 s) compared with the PL condition (86.2 ± 10.4 s). Our results suggest that GSE is effective in improving HRR kinetics during heightened sympathetic activity induced by MMA in young individuals (p = 0.034; ES = 0.4). Thus, regular treatment with GSE may provide a nonpharmacological intervention to reduce sympathetic hyperactivity in conditions where excessive sympathetic activity is consistently present.