title: Performance outcomes and unwanted side effects associated with energy drinks.
abstract: Energy drinks are increasingly popular among athletes and others. Advertising for these products typically features images conjuring great muscle power and endurance; however, the scientific literature provides sparse evidence for an ergogenic role of energy drinks. Although the composition of energy drinks varies, most contain caffeine; carbohydrates, amino acids, herbs, and vitamins are other typical ingredients. This report analyzes the effects of energy drink ingredients on prolonged submaximal (endurance) exercise as well as on short-term strength and power (neuromuscular performance). It also analyzes the effects of energy drink ingredients on the fluid and electrolyte deficit during prolonged exercise. In several studies, energy drinks have been found to improve endurance performance, although the effects could be attributable to the caffeine and/or carbohydrate content. In contrast, fewer studies find an ergogenic effect of energy drinks on muscle strength and power. The existing data suggest that the caffeine dose given in studies of energy drinks is insufficient to enhance neuromuscular performance. Finally, it is unclear if energy drinks are the optimal vehicle to deliver caffeine when high doses are needed to improve neuromuscular performance.
authors.affiliation: Exercise Physiology Laboratory at Toledo, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mora-Rodriguez
authors.forename: Jesús G
authors.initials: JG
authors.lastname: Pallarés
mesh_terms: D054874:Athletic Performance; D002110:Caffeine / Q000009:adverse effects / Q000494:pharmacology*; D019587:Dietary Supplements / Q000009:adverse effects; D061215:Energy Drinks / Q000009:adverse effects; D015444:Exercise / Q000502:physiology*; D006801:Humans; D053580:Muscle Strength / Q000187:drug effects*; D058573:Performance-Enhancing Substances / Q000009:adverse effects / Q000494:pharmacology*; D010807:Physical Endurance / Q000187:drug effects; D014882:Water-Electrolyte Balance / Q000187:drug effects
chemical_list: D058573:Performance-Enhancing Substances; D002110:Caffeine
keywords: Red Bull; caffeine; endurance performance; energy drinks; neuromuscular performance; side effects; taurine