In recent years the energy drink market has exploded, with more people than ever before turning to these products as quick ‘pick me ups’, whether to stay awake during all night study vigils or gain the edge in sport,” said Dr Cameli. “With energy drinks containing both caffeine and taurine concerns have been raised of adverse effects on the heart. While caffeine increases blood pressure, studies suggest that taurine may stimulate the release of calcium from the sarcoplasmic reticulum.”
In the current study the researchers used speckle-tracking echocardiography, the avant-garde technique in echocardiography, and echo Doppler analysis to explore the influence of energy drinks on heart function.
For the study 35 healthy subjects (mean age 25 years), drank a body surface area indexed amount of an energy drink (168 ml/m2) containing caffeine and taurine.
Assessments of heart rate, blood pressure, left ventricular function and right ventricular function were undertaken at baseline and one hour after consumption.
Figure 1 shows the relative changes from baseline in heart rate, blood pressure and left and right ventricular parameters one hour after consuming the energy drink. Heart rate increased by 1.2% (p=ns [not significant]), systolic blood pressure increased by 2.6% (p=ns) and diastolic blood pressure increased by 6% (p=0.02). Dr Cameli said: “This confirms that a standard energy drink consumption induces a light increase in diastolic blood pressure.”
Left ventricular function improved in comparison to baseline. Ejection fraction increased by 5% (p=0.01), mitral annular plane systolic excursion (MAPSE) (which evaluates longitudinal ventricular function) increased by 11% (p<0.001), global longitudinal strain increased by 10% (p=0.004), and torsion (left ventricular twisting) increased by 22% (p<0.0001).
Right ventricular function was also improved one hour after consuming energy drinks. Right ventricular fractional area change (RVFAC) increased by 2% (p=0.09), tricuspid annular plane systolic excursion (TAPSE) increased by 15% (p<0.0001), and global and free wall right ventricular longitudinal strain (RVLS), (a measurement of longitudinal strain of the right ventricle), increased by 8% (p=0.001) and 5% (p=0.1) respectively.
Figure 1: Relative changes from baseline in heart rate, blood pressure and left and right ventricular parameters 1 hour after energy drink consumption
MAPSE: mitral annular plane systolic excursion; RVFAC: right ventricular fractional area change; TAPSE: tricuspid annular plane systolic excursion; RVLS: right ventricular longitudinal strain.
“Taken together these results show that energy drinks enhance contractions of both the left and right ventricles, thereby delivering a positive effect on myocardial function,” said Dr Cameli. “This could be explained by the inotropic effect of taurine that, as previously demonstrated, stimulates the release of calcium from the sarcoplasmic reticulum.”
He continued: “Our study was performed in young healthy individuals at rest. Future studies need to focus on whether such benefits persist after long term consumption of energy drinks, and what the effects are of consuming these drinks during physical activity. It will also be important to determine which of the effects are induced in patients with cardiac disease to further our understanding of the potential benefits or risks of energy drink consumption.”
Matteo Cameli1, Daniele Menci1, Sergio Mondillo1
1University of Siena, Italy