A single dose of dark chocolate increases parasympathetic modulation and heart rate variability in healthy subjects

• Published in: Revista de Nutrição 2016-12, Vol.29 (6), p.765-773
• Main Authors: DUARTE, Ana Amélia Machado, MOSTARDA, Cristiano, IRIGOYEN, Maria Claudia, RIGATTO, Katya
• Format: Article
• Language: English
• Subjects: NUTRITION & DIETETICS
• ISSN: 1415-5273; 1678-9865; 1415-5273
• DOI: 10.1590/1678-98652016000600002

ABSTRACT Objective: The aim of this study was to investigate the acute effect of a single dose of dark chocolate (70% cocoa) on blood pressure and heart rate variability. Methods: Thirty-one healthy subjects (aged 18-25 years; both sexes) were divided into two groups: 10 subjects in the white chocolate (7.4 g) group and 21 in the dark chocolate (10 g) group; measurements were performed at the university's physiology lab. An electrocardiogram measured the sympathovagal balance by spectral and symbolic analysis. Results: A single dose of dark chocolate significantly reduced systolic blood pressure and heart rate. After consuming 10 g of dark chocolate, significant increases were observed for heart rate variability, standard deviation of RR intervals standard deviation of all NN intervals, square root of the mean squared differences between adjacent normal RR intervals root mean square of successive differences, and an increase in the high frequency component in absolute values, representing the parasympathetic modulation. Conclusion: In conclusion the importance of our results lies in the magnitude of the response provoked by a single dose of cocoa. Just 10 g of cocoa triggered a significant increase in parasympathetic modulation and heart rate variability. These combined effects can potentially increase life expectancy because a reduction in heart rate variability is associated with several cardiovascular diseases and higher mortality. RESUMO Objetivo: O objetivo deste estudo foi investigar o efeito agudo de uma única dose de chocolate amargo (70% cacau) sobre a pressão arterial e a variabilidade da frequência cardíaca. Métodos: Trinta e um indivíduos saudáveis (com idade entre 18-25 anos; ambos os sexos) foram divididos em dois grupos: 10 indivíduos no grupo chocolate branco (7,4 g) e 21 no grupo chocolate amargo (10,0 g); as avaliações foram realizadas no laboratório de fisiologia da Universidade Federal de Ciências da Saúde de Porto Alegre. Resultados: O eletrocardiograma foi realizado para analisar o balanço simpatovagal através da análise espectral e simbólica. Uma única dose de chocolate amargo reduziu significativamente a pressão arterial sistólica e a frequência cardíaca. Depois de consumir 10 g de chocolate amargo, observou-se aumento significativo na variabilidade da frequência cardíaca, o desvio padrão dos intervalos, a raiz quadrada da média do quadrado das diferenças entre os intervalos RR normais adjacentes a raiz quadrada da média da soma dos