 Energy drinks are increasingly popular among a young and male crowd, marketed as enhancing focus, performance at athletic or intellectual tasks, but also sometimes marketed as club drinks, edgy recreational drugs, and party aids. Long-term exposure to the various components of energy drinks may result in significant alterations in the cardiovascular system, and the safety of energy drinks has not been fully established. We will attempt to answer the very simple question, is it safe for me to drink any energy beverage? Red Bull was introduced in Austria in 1987 and in the United States in 1997. Since then, the energy beverage market has grown exponentially. Hundreds of different brands are now marketed with caffeine content ranging from modest 50 mg to an alarming 505 mg per can or bottle, equivalent to 5 cups of coffee. In the United States, Red Bull enjoyed a 65% share of the $650 million energy drink market in 2005, and its sales are growing at about 35% per year. The United States is the world's largest consumer of energy drinks by volume, roughly 290 million gallons in 2007, or 3.0 quarts per person per year. Consumption of energy drinks is most common among those aged 11-35 years, and 24-57% of this age group reported that they drank an energy drink within the past few months. Recent studies have shown energy drink consumption to be positively associated with high-risk behavior, including marijuana use, sexual risk-taking, fighting, failure-to-use seatbelts, and taking risks on a dare, as well as with smoking, drinking, problems stemming from alcohol abuse, and illicit drug use. Clinical evidence demonstrates the behavioral stimulant effect of caffeine. It seems quite likely that caffeine enhances human performance on some types of tasks, for example, maintaining vigilance, especially among people who are not already adapted to caffeine. Among high-dose habitual consumers, performance enhancements above and beyond reversing withdrawal are likely to be modest at best. The potential adverse effects of caffeine use, when not mixed with alcohol, are termed caffeine intoxication. Common features of caffeine intoxication include nervousness, anxiety, restlessness, insomnia, gastrointestinal upset, tremors, tachycardia, psychomotor agitation, and in very rare cases, death. In addition to caffeine intoxication, the consumption of energy drinks has been linked to seizures, acute mania, and stroke. Deaths attributed to energy drink consumption have been reported in Australia, Ireland, and Sweden. Considerable debate has ensued as to whether these fatalities were a direct result of energy drink consumption. There is an association between the heavy use of caffeine and the heavy use of alcohol, and the ingestion of energy drinks in combination with alcohol is becoming increasingly popular, with 24% of a large stratified sample of college students reporting such consumption within the last 30 days. In a survey of 496 college students, 27% reported mixing alcohol and energy drinks in the past month. Of those that mixed energy drinks in alcohol, 49% used more than three energy drinks per occasion when doing so. In a survey of 1,253 college students, energy drink users were disproportionately male and consumed alcohol more frequently than non-energy drink users. One study showed that ingestion of a caffeinated energy drink, Red Bull, with vodka reduced participants' perception of impairment of motor coordination, in comparison to vodka alone, but did not significantly reduce objective measures of alcohol-induced impairment of motor coordination, reaction time, or breath alcohol concentration. Thus, when mixing energy drinks in alcohol, users may not feel the symptoms of alcohol intoxication. This may increase the potential for alcohol-related injury. Indeed, a recent survey of college students found that in comparison to those who consumed alcohol alone, students who consumed alcohol mixed with energy drinks had a significantly higher prevalence of alcohol-related consequences, including being taken advantage of, or taking advantage of another student sexually, riding in an automobile with a driver under the influence of alcohol, or being hurt or injured. Studies in adult twins show that lifetime caffeine intake, caffeine toxicity, and caffeine dependence are significantly and positively associated with various psychiatric disorders, including major depression, generalized anxiety disorder, panic disorder, antisocial personality disorder, alcohol dependence, and cannabis and cocaine abuse or dependence. More specifically with regard to cigarette smoking, human and animal studies show that caffeine increases the reinforcing effect of nicotine. Epidemiology studies show that cigarette smokers consume more caffeine than non-smokers, an effect that may be partially due to the increased caffeine metabolism among cigarette smokers. With regards to the other components of energy drinks like Red Bull, none of them appear to be present at levels that would produce either a positive or negative effect. Taurine, for example, which is a sulfur-containing amino acid, does have an effect on metabolism. But the amount present, even in several Red Bulls, is still significantly below the level that has any measurable effect. The amounts of guarana, taurine, and ginseng found in popular energy drinks are also far below the amounts expected to deliver either therapeutic benefits or adverse events. However, both caffeine and sugar are present in amounts known to cause a variety of adverse health effects. The amount of sugar provided in one can, or 500 milliliters, of an energy drink is typically about 54 grams. A teaspoon of sugar weighs about 4 grams, so a typical energy drink contains about 13 teaspoons, or just more than one-quarter cup of sugar. Long-term exposure of the body to excesses of simple sugars is associated with the development of obesity and insulin resistance. Pancreatic beta cells increase insulin secretion in response to this reduction in insulin sensitivity. Over time, in many individuals, the beta cells become unable to secrete sufficient insulin to maintain normal blood glucose levels, leading to the development of diabetes. In conclusion, one can of an energy drink during one session is safe for most healthy individuals. However, excess consumption and consumption with other caffeine-containing beverages or alcohol may lead to adverse effects and possibly death. Patients with clinically relevant underlying medical conditions, including heart disease and hypertension, should consult with their physician before drinking any energy drinks. Thanks for watching.