martes, 12 de febrero de 2013
Pseudoephedrine and Preexercise Feeding: Influence on Performance
Pritchard-Peschek, Kellie R.; Osborne, Mark A.; Slater, Gary J.; Taaffe, Dennis R.; Jenkins, David G.
Purpose: This study examined the influence of pre-exercise food intake on plasma PSE concentrations and subsequent high intensity exercise. Additionally, urinary PSE concentrations were measured under the same conditions and compared to the present WADA threshold.
Methods: Ten highly trained male cyclists and triathletes (age 30.6 +/- 6.6 years, body mass 72.9 +/- 5.1 kg, O2max 64.8 +/- 4.5 ml[middle dot]kg-1min-1) undertook four cycling time trials (TTs) each requiring the completion of a set amount of work (7 kJ[middle dot]kg-1 BM) in the shortest possible time. Participants were randomized into a fed or non-fed condition and orally ingested 2.8 mg[middle dot]kg-1 BM of PSE or a placebo (PLA) 90 min before exercise; in the fed trials, they consumed a meal providing 1.5 g[middle dot]kg-1 BM of carbohydrate. Venous blood was sampled at 30, 50, 70 min and pre-warm up and post-exercise for the analysis of plasma PSE and catecholamine concentrations, urine was also collected for the analysis of PSE concentration.
Results: Independent of the pre-exercise meal, 2.8 mg[middle dot]kg-1 BM of PSE did not significantly improve cycling TT performance. The fed trials resulted in lower plasma PSE concentrations at all time points compared to the non-fed trials. Both plasma epinephrine and blood lactate concentrations were higher in the PSE compared to the placebo trials and pre- and post-exercise urinary PSE concentrations were significantly higher than the threshold (150 [mu]g[middle dot]mL-1) used by WADA to determine illicit PSE use.
Conclusions: Irrespective of the pre-exercise meal, cycling TT performance of ~30 min was not improved following PSE supplementation. Furthermore, 2.8 mg[middle dot]kg-1 BM of PSE taken 90 min before exercise, with or without food, resulted in urinary PSE concentrations exceeding the present WADA threshold.
(C) 2013The American College of Sports Medicine