Acute dopamine reuptake inhibition enhances performance in warm, but not in temperate conditions

Bart Roelands, Hiroshi Hasegawa, P. Watson, Luk Buyse, Guido De Schutter, Maria Francesca Piacentini, Romain Meeusen

Onderzoeksoutput: Meeting abstract (Book)

Samenvatting

Introduction
Previously, we reported that acute dual dopamine/noradrenaline (DA/NA) reuptake inhibition (bupropion) significantly altered the hormonalresponse to exercise in temperate conditions (Piacentini, 2004) and significantly improved time trial performance in the heat (30°C;Watson, 2005). The aim of the present study was to determine which neurotransmitter system is responsible for the improved performancein the heat. Therefore we studied the effects of acute administration of a DA reuptake inhibitor.MethodsEight healthy well-trained male cyclists (Age 26,0±4,7y; Ht 182±6cm; Body Mass 77,9±6,4kg; Wmax 361±18W) participated in this study.Subjects completed a preliminary maximal exercise test, a familiarization trial and four experimental trials, two temperate (18°C) and twowarm trials (30°C), in a double blind-randomized crossover design. Subjects ingested either a placebo (PLAC; lactose 20mg) or Ritalin(RIT;20mg) one hour before the start of exercise. Subjects cycled for 60 min at 55% Wmax, immediately followed by a time trial to measureperformance. Core temperature (Tcore), skin temperature, heart rate, sweat loss, ratings of perceived exertion (RPE), thermal comfort,blood lactate and hormonal data were recorded. Statistical analysis were conducted using two-way (temperature-by-drug) repeatedmeasures ANOVA to evaluate differences between and within trials. The significance level was set at p<0,05.ResultsExercise performance was not influenced by RIT in temperate conditions (P=0.397), but subjects completed the TT 16% faster in the RIT trial(38.1±6.4min) than in the placebo (45.4±7.3min; P=0.049) when exercise was performed in a warm environment. Power output washigher in the RIT trial in the heat, compared to the PLAC trial (P<0.05). Tcore was not different between conditions in the temperate trials. Inthe heat Tcore was significantly higher at rest (P=0.009), at the start of exercise and throughout the TT (P<0.05) in the RIT trial. Throughoutthe TT with RIT heart rates were significantly higher during exercise in the heat at all times (P<0.05). After the 60 minutes of fixed intensityexercise in the heat subjects’ RPE were significantly higher (P=0.034) in the placebo than in observed in the RIT trial.Discussion/ConclusionThese data indicate that acute RIT administration enhanced performance by 16%. No such effect was apparent under temperate conditions.The present findings support previous work suggesting that higher DA activity increases tolerance to exercise in the heat (Bridge,2003), increased catecholaminergic neurotransmission enhances exercise performance in a warm environment (Watson et al. 2005) andthat dopamine may influence thermoregulation during exercise (Hasegawa, 2000).
Originele taal-2English
TitelBook of Abstracts of the 11th Annual Congress of the European College of Sport Science
Pagina's38-38
Aantal pagina's1
StatusPublished - 2006
Evenement11th Annual Congress of the European College of Sport Science - Lausanne, Switzerland
Duur: 5 jul 20068 jul 2006

Conference

Conference11th Annual Congress of the European College of Sport Science
Verkorte titelECSS 2006
LandSwitzerland
StadLausanne
Periode5/07/068/07/06

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