Effects of Single and Multiple Energy Shots on Blood Pressure and Electrocardiographic Parameters.Am J Cardiol. 2016 Feb 01; 117(3):465-8.AJ
We assessed the effects of single and multiple caffeinated energy shots on hemodynamic and electrocardiographic (ECG) parameters. This was a randomized, double-blinded, placebo-controlled, crossover study in otherwise healthy volunteers (n = 26) where a caffeinated energy shot or matching placebo was ingested. The study drink was consumed twice daily for 7 days during each phase, with a 7-day washout period in between. The primary end points of interest were systolic and diastolic blood pressure (BP), heart rate, PR interval, QRS duration, and QT and QTc intervals. All parameters were evaluated at baseline, 1, 3, and 5 hours on the first and seventh day of each phase. Systolic BP after a single energy shot consumption was significantly higher than placebo at 3 and 5 hours (p = 0.050 and p = 0.038, respectively). Similarly, diastolic BP after a single energy shot consumption was significantly higher at 1 and 5 hours (p = 0.019 and p = 0.043, respectively). The systolic and diastolic BP elevations were not significant after consistent consumption (all p values ≥ 0.079). None of the ECG parameters were significantly affected (all p values ≥ 0.108) compared with placebo. In conclusion, a single shot of a caffeinated energy drink significantly raised systolic and diastolic BPs. However, these elevations were not sustained with chronic consumption. ECG parameters were not altered.