Somers, Krishen

Introduction: The popularity of energy drinks among young adults is rising. Warnings have been issued regarding potential health risks including adverse cardiovascular complications. We and others have previously shown that energy drink consumption increases blood pressure. The mechanisms are not fully understood. Hypothesis: We hypothesized that increase in blood pressure after drinking a commercially available energy drink, compared to a placebo, is secondary to increased sympathetic activation. Methods: In a randomized, double-blind, placebo-controlled, cross-over study, we studied 25 healthy subjects, age 29±1 years, who were free of known disease, had no known cardiovascular risk factors, and were not on any medications. Each subject consumed a can, 16-fluid ounces, of Rockstar energy drink or a placebo drink in random order on two separate days. Blood pressure (n=25) and plasma norepinephrine levels (n=23) were measured before and 30-minutes after drink consumption. Results: Despite the increase in blood pressure after drinking Rockstar energy drink, which would be expected to elicit reflex reductions in central sympathetic outflow, plasma norepinephrine levels increased markedly after energy drink consumption vs placebo (73.6±9.7% vs 30.9±9.7%, respectively, P=0.003; Figure). Specifically, plasma norepinephrine levels increased from 149.8±11.7pg/ml to 249.8±17.3pg/ml after the energy drink consumption and from 139.9±11.7pg/ml to 178.6±17.3pg/ml after placebo (P=0.0007 for timeхtreatment comparison). Conclusions: Increased blood pressure after consumption of commercially available energy drink is associated with significantly increased catecholamine levels in young healthy adults. These acute hemodynamic and adrenergic changes may predispose to increased cardiovascular risk by triggering arrhythmias or ischemia, particularly in individuals with a vulnerable cardiovascular substrate.

Introduction: An increasing number of healthy adults consume energy drinks to enhance their physical and mental performance. Energy drinks contain caffeine and multiple other “natural” stimulants and their combined effects on cardiac hemodynamics in healthy individuals are unclear. Hypothesis: We hypothesized that drinking a commercially available energy drink, Rockstar , compared to a placebo drink, increases resting blood pressure and heart rate in healthy adults, and these increases would be further accentuated by stress conditions. Methods: We enrolled 25 healthy, normotensive subjects (14 males), aged 29±1 years, with body mass index 24.5±1 kg/m 2 , in a randomized, double-blind, placebo-controlled, crossover study. Each subject consumed a placebo drink and a commercially available Rockstar energy drink (473 ml), in random order on two separate study days. Blood pressure and heart rate responses were recorded and compared before and 30 minutes after drink consumption, both at rest and then in response to physical, mental and cold stressors. Results: The Rockstar energy drink induced a 6±1% increase in resting systolic blood pressure, compared to 3±1% with the placebo drink (P=0.0078). Diastolic blood pressure increased by 7±1% vs 0±1% with the placebo drink (P=0.0007; Figure 1). Heart rate increased similarly in both groups, by 5±2% in the energy drink group vs. 7±2% in the placebo group. Blood pressure and heart rate increases during the stress stimuli (sustained handgrip, mental stress and cold stress) did not differ between energy drink and placebo. Conclusions: Drinking a commercially available Rockstar energy drink significantly increases resting blood pressure in young healthy adults. Blood pressure increases are not further accentuated by exercise, mental or cold pressor stress stimuli. These hemodynamic changes induced by energy drink consumption could predispose to cardiovascular events.