title: The blood pressure-elevating effect of Red Bull energy drink is mimicked by caffeine but through different hemodynamic pathways.
abstract: The energy drink Red Bull (RB) has recently been shown to elevate resting blood pressure (BP) and double product (reflecting increased myocardial load). However, the extent to which these effects can be explained by the drink's caffeine and sugar content remains to be determined. We compared the cardiovascular impact of RB to those of a comparable amount of caffeine, and its sugar-free version in eight young healthy men. Participants attended four experimental sessions on separate days according to a placebo-controlled randomized crossover study design. Beat-to-beat hemodynamic measurements were made continuously for 30 min at baseline and for 2 h following ingestion of 355 mL of either (1) RB + placebo; (2) sugar-free RB + placebo; (3) water + 120 mg caffeine, or (4) water + placebo. RB, sugar-free RB, and water + caffeine increased BP equally (3-4 mmHg) in comparison to water + placebo (P < 0.001). RB increased heart rate, stroke volume, cardiac output, double product, and cardiac contractility, but decreased total peripheral resistance (TPR) (all P < 0.01), with no such changes observed following the other interventions. Conversely, sugar-free RB and water + caffeine both increased TPR in comparison to the water + placebo control (P < 0.05). While the impact of RB on BP is the same as that of a comparable quantity of caffeine, the increase occurs through different hemodynamic pathways with RB's effects primarily on cardiac parameters, while caffeine elicits primarily vascular effects. Additionally, the auxiliary components of RB (taurine, glucuronolactone, and B-group vitamins) do not appear to influence these pathways.
authors.affiliation: Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Miles-Chan
authors.affiliation: Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Charrière
authors.affiliation: Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Erik K
authors.initials: EK
authors.lastname: Grasser
authors.affiliation: Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Montani
authors.affiliation: Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
authors.forename: Abdul G
authors.initials: AG
authors.lastname: Dulloo
keywords: Blood pressure; caffeine; energy drink; hemodynamics