Effect of caffeinated versus noncaffeinated energy drinks on central blood pressures.

Study Objective: To evaluate the effects of caffeinated energy shots compared with noncaffeinated energy shots as assessed by changes in peripheral and central hemodynamic parameters in healthy subjects.

Design: Randomized, double-blind, controlled crossover study.

Setting: University campus.

Patients: Ten healthy volunteers.

Measurements And Main Results: Subjects were randomized to receive either a caffeinated or noncaffeinated energy shot; after a minimum 6 days washout period, subjects were given the alternate energy shot. Peripheral blood pressures, and central hemodynamic parameters, were assessed and recorded for each subject at baseline and at 1 and 3 hours after consumption of the energy shots. Peripheral systolic blood pressure (SBP) increased significantly with the caffeinated energy shot compared with noncaffeinated (8.30 ± 4.19 mm Hg and -0.20 ± 5.55, respectively, p=0.009) at 3 hours. Central SBP increased significantly with the caffeinated energy shot compared with noncaffeinated (8.00 ± 4.03 mm Hg and 1.50 ± 6.57, respectively, p=0.045) at 3 hours. Peripheral and central diastolic blood pressure were nonsignificantly higher with the caffeinated energy shot at 3 hours. Peripheral and central pulse pressure were consistently higher with consumption of the caffeinated beverage. Heart rate, augmentation index, pulse pressure amplification ratio, ejection duration and Subendocardial Viability Ratio were not different between the two interventions over time. P1 height was significantly higher with the caffeinated shot compared with the noncaffeinated shot at both 1 and 3 hours (p=0.035 and 0.013, respectively). Three and one subjects experienced an adverse effect with the caffeinated and noncaffeinated shot, respectively.

Conclusion: A caffeinated energy shot acutely increases peripheral and central SBPs compared with a noncaffeinated energy shot. Larger studies with a placebo comparator are needed to assess the significance of peripheral and central hemodynamic changes with noncaffeinated energy drinks.