Acute effects of caffeine intake on athletic performance: A systematic review and meta-analysis

Abstract

© 2017, Sociedad Chilena de Nutricion Bromatologia y Toxilogica. All rights reserved. Objective: Our objective was to perform a systematic review and meta-analysis of the research literature assessing the effect of caffeine on athletic performance. Methods: A total of 13 studies published between 2010 and 2015 were included in the meta-analysis of the effects of caffeine on maximum running distance (2 studies), time trial performance (7 studies), and muscle power (4 studies). The effect sizes were calculated as standardized differences in means (std in means). Meta-analysis was completed using a random effects model. Results: Caffeine supplementation did not increase maximum running distance (effect size= 0.37, p= 0.14) and muscle power (effect size= 0.17, p= 0.36). However, improvements were observed in the time trial performance (effect size= -0.40, p< 0.01). Subgroup analyses revealed that the improvement in time trial results may be related to the use of the 6 mg/kg of body weight of caffeine dose (effect size= -0.45, p= 0.01). Conclusion: Our meta-analysis showed that caffeine intake does not improve performance in maximum running distance and muscle power, but it seems to improve time trial performance. The effect of caffeine on time trial performance related to dose.