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Caffeine withdrawal and high-intensity endurance cycling performance
C. Irwin, B. Desbrow, A. Ellis, Brooke O'Keeffe, G. Grant, M. Leveritt
Abstract In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine cons…
Abstract In this study, we investigated the impact of a controlled 4-day caffeine withdrawal period on the effect of an acute caffeine dose on endurance exercise performance. Twelve well-trained and familiarized male cyclists, who were caffeine consumers (from coffee and a range of other sources), were recruited for the study. A double-blind placebo-controlled cross-over design was employed, involving four experimental trials. Participants abstained from dietary caffeine sources for 4 days before the trials and ingested caspulses (one in the morning and one in the afternoon) containing either placebo or caffeine (1.5 mg · kg−1 body weight · day−1). On day 5, capsules containing placebo or caffeine (3 mg · kg−1 body weight) were ingested 90 min before completing a time trial, equivalent to one hour of cycling at 75% peak sustainable power output. Hence the study was designed to incorporate placebo–placebo, placebo–caffeine, caffeine–placebo, and caffeine–caffeine conditions. Performance time was significantly improved after acute caffeine ingestion by 1:49 ± 1:41 min (3.0%, P = 0.021) following a withdrawal period (placebo–placebo vs. placebo–caffeine), and by 2:07 ± 1:28 min (3.6%, P = 0.002) following the non-withdrawal period (caffeine–placebo vs. caffeine–caffeine). No significant difference was detetcted between the two acute caffeine trials (placebo–caffeine vs. caffeine–caffeine). Average heart rate throughout exercise was significantly higher following acute caffeine administration compared with placebo. No differences were observed in ratings of perceived exertion between trials. A 3 mg · kg−1 dose of caffeine significantly improves exercise performance irrespective of whether a 4-day withdrawal period is imposed on habitual caffeine users.
Published in Jurnal sport science
1
 6 2011