Evaluation of the Effects of Different Energy Drinks and Coffee on Endothelial Function

Abstract

Endothelial function plays an important role in circulatory physiology. There has been differing reports on the effect of energy drink on endothelial function. We set out to evaluate the effect of 3 energy drinks and coffee on endothelial function. Endothelial function was evaluated in healthy volunteers using a device that uses digital peripheral arterial tonometry measuring endothelial function as the reactive hyperemia index (RHI). Six volunteers (25 ± 7years) received energy drink in a random order at least 2days apart. Drinks studied were 250ml "Red Bull" containing 80mg caffeine, 57ml "5-hour Energy" containing 230mg caffeine, and a can of 355ml "NOS" energy drink containing 120mg caffeine. Sixteen volunteers (25 ± 5years) received a cup of 473ml coffee containing 240mg caffeine. Studies were performed before drink (baseline) at 1.5 and 4hours after drink. Two of the energy drinks (Red Bull and 5-hour Energy) significantly improved endothelial function at 4hours after drink, whereas 1 energy drink (NOS) and coffee did not change endothelial function significantly. RHI increased by 82 ± 129% (p= 0.028) and 63 ± 37% (p= 0.027) after 5-hour Energy and Red Bull, respectively. The RHI changed after NOS by 2 ± 30% (p= 1.000) and by 7 ± 30% (p= 1.000) after coffee. In conclusion, some energy drinks appear to significantly improve endothelial function. Caffeine does not appear to be the component responsible for these differences.