The effect of a caffeinated energy drink on various psychological measures during submaximal cycling

Caffeine containing energy drinks is commonly consumed in the belief that it will enhance the quality of an exercise session and enhance mood. However, studies examining their efficacy are sparse. The aim of this study was to examine the effect of a caffeinated energy drink on leg pain perception, perceived exertion, mood state and readiness to invest effort pre, during and post 60min cycling exercise. Fourteen active individuals (7 males, 7 females, mean age±S.D.=23.5±3.5years), completed two 60min cycling trials at an intensity of 60% VO2 max preceded by ingestion of solutions containing either a caffeinated energy drink or placebo using a double-blind, deceptive, crossover design. During exercise, RPE (6-20 scale), leg pain (0-10 scale), heart rate (HR) and blood lactate (Bla) were recorded. Participants also completed measures of mood state and readiness to invest physical effort (RTIPE) pre- and post-exercise. Repeated measures analysis of variance was used to assess differences in all variables and across time and treatments, with gender used as a between subjects variable. Results indicate that HR was significantly higher (P=.002) from 30 to 60min and RPE (P=.0001) and pain perception (P=.0001) were significantly lower from 20 to 60min in the energy drink condition compared to placebo. Bla was significantly higher (P=.021) in the last 15min of the energy drink trial and RTIPE (P=.001) increased significantly more from pre-ingestion to pre-exercise post-ingestion in the energy drink condition compared to placebo. No gender differences were evident (P>.05). The data revealed positive effects of energy drink ingestion on perception of exertion, leg muscle pain perception and readiness to invest effort during submaximal cycling in active adults.