Failure of caffeine to enhance exercise performance in incremental treadmill running

The effect of caffeine ingestion (5 mg.kg -1 BW 3.5 hours before exercise) on exercise performance in incremental treadmill running was investigated. Eight moderately trained runners (24.8 years; VO 2 max = 65.4 ml.kg -1 min -1 ), selected for their limited caffeine usage, performed two work capacity performance (WCP) tests to exhaustion following the ingestion of either caffeine or a gelatin placebo. Performance variables of running time to exhaustion (TE), maximal oxygen consumption (VO 2 max), and lactate threshold (LT) were all unaltered following caffeine ingestion. Compared with placebo, caffeine ingestion resulted in significantly higher increases in heart rate (HR), expired minute ventilation (VE) and blood lactic acid concentration (HLa) during submaximal exercise (warm-up and five 3 minute incremental exercise stages). Ratings of perceived exertion (RPE) were also lowered during the latter stages of exercise in the caffeine trial but the feeling of a lessened somatic discomfort did not result in improvements in exercise performance. It was concluded that caffeine, in the dosage ingested, has significant physiological effects, yet may have few ergogenic properties under incremental exercise conditions.