Influence of perceived caffeine ingestion upon submaximal exercise to exhaustion

Abstract

Each Ss performed the two submaximal tests to exhaustion after taking an artificially sweetened lemonade beverage labeled "caffeine" previous to one test and a beverage labeled "noncaffeine" previous to the other test. The order of the tests was randomly chosen. Respiratory gases were analysed and heart rates were monitored for cross-country runners (n=l3) from the University of Wisconsin-LaCrosse, who ran 40-60 mi/wk, while each performed a V02 max test and two submaximal tests on a treadmill. The workload at which the subjects ran during the submaximal tests was determined by the grade and speed at which they reached , approximately 85% of their V0 2 max during the initial max test. A dependent t-test performed on the times to exhaustion, RPE's at minutes 2 and 12, heart rates, and RER's between the caffeine and noncaffeine trials revealed no significant differences (p < .05; t > 1.356) for any of these parameters. The results indicated that the belief that the subjects had taken a significant amount of caffeine did not produce a significant change in endurance performance.