Effects of acute cocoa ingestion on arterial baroreflex sensitivity in humans

Introduction: Daily cocoa intake is reported to decrease cardiovascular-related mortality. It is suggested that cocoa ingestion may improve autonomic modulation. Arterial baroreflex is a crucial autonomic regulator. However, the effect of cocoa on cardiovagal baroreflex sensitivity (CBRS) has not been understood thoroughly. Aims/Hypothesis: We aimed to investigate the effect of cocoa ingestion on CBRS. We hypothesized that cocoa ingestion would increase CBRS in a dose-dependent manner. Methods: Seventeen healthy older adults (61 ± 8yrs; M/F, N=8/9) participated in the study. Five trials were conducted with drinks containing 0, 2, 5, 13, and 26 grams of cocoa, respectively. All drinks had the same amount of other ingredients (e.g., sugar). The 5 trials were randomized, double-blinded, at least 72 hours apart, and conducted at the same morning time. Two hours after ingesting the experimental drink, beat-by-beat heart rate (HR) and blood pressure (BP) were recorded in a supine position during the study. Spontaneous CBRS was calculated from the beat-by-beat systolic BP and R-R interval data using a sequence method. Results: There were no significant differences in BP and HR after ingesting the drink across all visits (repeated measures ANOVA; p>0.05). Cocoa ingestion dose-dependently decreased CBRS (Figure 1; repeated measures ANOVA, P=0.009). CBRS after 26g of cocoa was significantly lower than after 0g (12.1±5.7 vs. 18.2±7.7 ms/mmHg, P=0.018). CBRS was significantly and negatively correlated with cocoa amount (R=-0.35, P=0.003). Conclusion: Contrary to our hypothesis, the data show that acute cocoa ingestion dose-dependently decreased CBRS. Prior reports suggest that decreased CBRS is associated with cardiovascular events. Therefore, the effect of cocoa in decreasing CBRS should be noted, while the beneficial effects of cocoa were suggested by prior reports. Further studies are needed to verify which component of cocoa (e.g., flavonoid, polyphenols, etc.) altered CBRS and how it will affect hemodynamics in humans including patients with cardiovascular diseases. Supported by NIH R01 HL144781 and HL164571 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.