THE ASTHMATIC ATHLETE - METABOLIC AND VENTILATORY RESPONSES TO EXERCISE WITH AND WITHOUT PREEXERCISE MEDICATION

To determine whether asthmatic athletes have normal physiological resp onses to exercise without pre-exercise medication, we studied 17 femal e and male asthmatic subjects, 9 highly trained (HT) and 8 moderately trained (MT) under 2 conditions: salbutamol (S) 200 mu g taken via inh aler 15 minutes prior to exercise or placebo (PL). The exercise task w as 4 continuous 5 minute increments representing 25, 50, 75 and 90% of the subject's VO(2)max. VO2, minute ventilation (V-E), respiratory ex change ratio (RER), % saturation (SaO(2)), and HR were continuously me asured during exercise. Blood lactate (LA) was measured each minute th roughout exercise and recovery. Post-medication, exercise; and recover y measurements of peak expiratory flow rates (PEFR) were made using a Mini-Wright flow meter. No differences, (p > 0.05) between treatment c onditions were found at any stage of exercise with respect to VO2, V-E , RER, HR and SaO(2). 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 pretreatm ent was S (S = 582; PL = 545 l . sec(-1); p = 0.003). During the exerc ise and recovery conditions mean PEFR measures were significantly high er (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% VO(2)max and 3 and 15 minutes into recovery. There was no dif ference 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 ventilator y responses during this incremental exercise protocol.