title: Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal.
abstract: This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.
authors.affiliation: Department of Biochemistry & Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Jane
authors.initials: J
authors.lastname: Shearer
authors.forename: Terry E
authors.initials: TE
authors.lastname: Graham
mesh_terms: D054874:Athletic Performance; D001786:Blood Glucose / Q000378:metabolism*; D002110:Caffeine / Q000009:adverse effects / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000009:adverse effects / Q000494:pharmacology; D061215:Energy Drinks / Q000009:adverse effects; D015444:Exercise / Q000502:physiology*; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D018482:Muscle, Skeletal / Q000187:drug effects*; D058573:Performance-Enhancing Substances / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D000697:Central Nervous System Stimulants; D058573:Performance-Enhancing Substances; D002110:Caffeine
keywords: caffeine; diabetes; energy drink; insulin resistance; performance; team sports