Cardio- and cerebrovascular responses to the energy drink Red Bull in young adults: a randomized cross-over study.
OBJECTIVE
Energy drinks are beverages containing vasoactive metabolites, usually a combination of caffeine, taurine, glucuronolactone and sugars. There are concerns about the safety of energy drinks with some countries banning their sales. We determined the acute effects of a popular energy drink, Red Bull, on cardiovascular and hemodynamic variables, cerebrovascular parameters and microvascular endothelial function.


METHODS
Twenty-five young non-obese and healthy subjects attended two experimental sessions on separate days according to a randomized crossover study design. During each session, primary measurements included beat-to-beat blood pressure measurements, impedance cardiography and transcranial Doppler measurements for at least 20 min baseline and for 2 h following the ingestion of either 355 mL of the energy drink or 355 mL of tap water; the endothelial function test was performed before and two hours after either drink.


RESULTS
Unlike the water control load, Red Bull consumption led to increases in both systolic and diastolic blood pressure (p < 0.005), associated with increased heart rate and cardiac output (p < 0.05), with no significant changes in total peripheral resistance and without diminished endothelial response to acetylcholine; consequently, double product (reflecting myocardial load) was increased (p < 0.005). Red Bull consumption also led to increases in cerebrovascular resistance and breathing frequency (p < 0.005), as well as to decreases in cerebral blood flow velocity (p < 0.005) and end-tidal carbon dioxide (p < 0.005).


CONCLUSIONS
Our results show an overall negative hemodynamic profile in response to ingestion of the energy drink Red Bull, in particular an elevated blood pressure and double product and a lower cerebral blood flow velocity.
Laboratory of Integrative Cardiovascular and Metabolic Physiology, Division of Physiology, Department of Medicine, University of Fribourg, Chemin du Musée 5, 1700, Fribourg, Switzerland, erikkonrad.grasser@unifr.ch.
Erik K
EK
Grasser
Gayathri
G
Yepuri
Abdul G
AG
Dulloo
Jean-Pierre
JP
Montani
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D001827:Body Height; D001835:Body Weight; D002319:Cardiovascular System / Q000187:drug effects*; D018592:Cross-Over Studies; D061215:Energy Drinks; D005260:Female; D064368:Healthy Volunteers; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D055815:Young Adult