Acute effects of energy drink consumption on microvascular reactivity in young male volunteers at rest: a randomized trial.

Energy drinks are nonalcoholic beverages whose main ingredients are sugar, taurine, and caffeine. The consumption of energy drinks is increasing worldwide, but only a few conflicting studies have investigated the vascular effects of energy drinks in young adults. The aim of this study was to evaluate microvascular reactivity before and after energy drinks consumption in young healthy male volunteers. This was a cross-sectional prospective study. Microvascular reactivity signals were evaluated in the skin of the forearm using laser speckle contrast imaging with acetylcholine (ACh) iontophoresis before and 90 and 180 min after the randomized consumption of one ED or the same volume of water (control), followed by a postocclusive reactive hyperemia (PORH) test. Thirty-two volunteers were evaluated (age: 25.4±4.3 years). Energy drink consumption prevented the rest-induced reduction in cutaneous vascular conductance over time that was observed in the control group. In the control group, there were significant reductions in microvascular vasodilation at 90 and 180 min compared to baseline (P=0.004), but this was not the case in the energy drink group (P=0.76). Our results demonstrated that the reduction in microvascular conductance associated with prolonged immobility can be prevented by the consumption of one energy drink, highlighting the vasodilator effects of this beverage in young individuals at rest. The between-study variability in terms of the brand of energy drinks and the ingested volume, as well as the method of vascular evaluation and the inclusion criteria, may explain the discrepancies among previous studies on the vascular effects of energy drinks.