CAFFEINE INGESTION AND PERFORMANCE OF A 1,500-METER SWIM

The purpose of this study was to evaluate the potential ergogenic bene fit of caffeine in the performance of a 1,500-meter swim. Caffeine (6 mg . kg(-1)) or placebo M,as administered 2-1/2 hrs prior to the swim trial in a double-blind crossover design. Caffeine resulted in a signi ficantly lower perceived exertion for 100-m warm-up swims. Subjects sw am significantly (p < 0.05) faster with caffeine (20:58.8 +/- 0:36.4, mean +/- SEM) than without (21:21.8 +/- 0:38). Plasma potassium was si gnificantly lower prior to the swim with caffeine, and blood glucose w as higher after that swim. Caffeine provides an ergogenic benefit for a 1,500-meter swim, an event that is completed in less than 25 min. Lo wer plasma potassium concentration prior to exercise and higher blood glucose following the trial suggest that electrolyte balance and gluco se availability May be important aspects of the ergogenic effects of c affeine.