Pseudoephedrine ingestion and cycling time-trial performance.
The aim of the current study was to investigate the effect of 180 mg of pseudoephedrine (PSE) on cycling time-trial (TT) performance. Six well-trained male cyclists and triathletes (age 33 +/- 2 yr, mass 81 +/- 8 kg, height 182.0 +/- 6.7 cm, VO2max 56.8 +/- 6.8 ml x kg(-1) x min(-1); M +/- SD) underwent 2 performance trials in which they completed a 25-min variable-intensity (50-90% maximal aerobic power) warm-up, followed by a cycling TT in which they completed a fixed amount of work (7 kJ/kg body mass) in the shortest possible time. Sixty minutes before the start of exercise, they orally ingested 180 mg of PSE or a cornstarch placebo (PLA) in a randomized, crossover, double-blind manner. Venous blood was sampled immediately pre- and postexercise for the analysis of pH plus lactate, glucose, and norepinephrine (NE). PSE improved cycling TT performance by 5.1% (95% CI 0-10%) compared with PLA (28:58.9 +/- 4:26.5 and 30:31.7 +/- 4:36.7 min, respectively). There was a significant Treatment x Time interaction (p = .04) for NE, with NE increasing during the PSE trial only. Similarly, blood glucose also showed a trend (p = .06) for increased levels postexercise in the PSE trial. The ingestion of 180 mg of PSE 60 min before the onset of high-intensity exercise improved cycling TT performance in well-trained athletes. It is possible that changes in metabolism or an increase in central nervous system stimulation is responsible for the observed ergogenic effect of PSE.
Pritchard-Peschek
Kellie R
KR
University of Queensland, Brisbane, Australia.
Jenkins
David G
DG
Osborne
Mark A
MA
Slater
Gary J
GJ
D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism; D000697:Central Nervous System Stimulants / Q000097:blood / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects*; D054199:Pseudoephedrine / Q000097:blood / Q000494:pharmacology*
D001786:Blood Glucose; D000697:Central Nervous System Stimulants; D007773:Lactates; D054199:Pseudoephedrine