The asthmatic athlete: metabolic and ventilatory responses to exercise with and without pre-exercise medication.
To determine whether asthmatic athletes have normal physiological responses to exercise without pre-exercise medication, we studied 17 female and male asthmatic subjects, 9 highly trained (HT) and 8 moderately trained (MT) under 2 conditions: salbutamol (S) 200 micrograms taken via inhaler 15 minutes prior to exercise or placebo (PL). The exercise task was 4 continuous 5 minute increments representing 25, 50, 75 and 90% of the subject's VO2max.VO2, minute ventilation (VE), respiratory exchange ratio (RER), % saturation (SaO2), and HR were continuously measured during exercise. Blood lactate (LA) was measured each minute throughout exercise and recovery. Post-medication, exercise, and recovery measurements of peak expiratory flow rates (PEFR) were made using a Mini-Wright flow meter. No differences (p > 0.05) between treatment conditions were found at any stage of exercise with respect to VO2, VE, RER, HR and SaO2. However, among the HT group the mean HR for the 4 exercise conditions was significantly higher under PL (PL = 151.7;S = 147.2; p = 0.01). No difference was found in LA during exercise or in recovery. Pre-exercise PEFR was significantly higher when pretreatment was S(S = 582; PL = 545 l.sec-1; p = 0.003). During the exercise and recovery conditions mean PEFR measures were significantly higher (S = 600.1; PL = 569.6; p = 0.002) with the S treatment. Bonferroni's test detected a difference in PEFR measures between S and PL at 25% and 50% VO2max and 3 and 15 minutes into recovery. There was no difference in the physiological response to exercise between groups based on training status. It was concluded that although S affects the PEFR these asthmatic athletes do not have altered metabolic or ventilatory responses during this incremental exercise protocol.
Ienna
T M
TM
School of Human Kinetics, University of British Columbia, Vancouver, Canada.
McKenzie
D C
DC
D000328:Adult; D000420:Albuterol / Q000008:administration & dosage / Q000627:therapeutic use*; D001250:Asthma, Exercise-Induced / Q000378:metabolism / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D016210:Methacholine Chloride; D009330:Nebulizers and Vaporizers; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010366:Peak Expiratory Flow Rate / Q000187:drug effects / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D010919:Placebos; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects / Q000502:physiology*; D012737:Sex Factors; D013177:Sports / Q000193:education / Q000502:physiology*
D016085:Bronchoconstrictor Agents; D001993:Bronchodilator Agents; D007773:Lactates; D010919:Placebos; D016210:Methacholine Chloride; D000420:Albuterol; D010100:Oxygen