Aerobic Conditioning in Mild Asthma Decreases the Hyperpnea of Exercise and Improves Exercise and Ventilatory Capacity

To determine the effect of an aerobicconditioning program on fitness, respiratory physiology, and restinglung function in patients with mild asthma. Prospective cohort study. Outpatientrehabilitation facility. Five patients withmild intermittent asthma and five normal control subjects completed a10-week aerobic conditioning program. Pulmonary function studies andnoninvasive cardiopulmonary exercise tests were performed before andafter the conditioning program. After aerobicconditioning, there were significant gains in maximum oxygenconsumption ( V˙o2max; 22.73 mL/kg/min vs25.29 mL/kg/min, p = 0.01, asthma; 22.94 mL/kg/min vs 27.85mL/kg/min, p = 0.03, control) and anaerobic threshold (0.99 L/min vs1.09 L/min, p = 0.03, asthma; 0.89 L/min vs 1.13 L/min, p = 0.01,control) in both groups. Although FEV1 was unchanged, themaximum voluntary ventilation (MVV) improved in the asthma group (96.0L/min vs 108.2 L/min, p = 0.08, asthma; 134.0 L/min vs 131.2 L/min,p = 0.35, control). During exercise, minute ventilation( V˙e) for each level of work was decreased in theasthma group after conditioning, while little change occurred in thecontrol group (68.48 L/min vs 51.70 L/min at initial V˙o2max, p = 0.02, asthma; 65.82 L/minvs 63.12 L/min at initial V˙o2max,p = 0.60, control). A significant decrease in the ventilatoryequivalent ( V˙e/oxygen consumption, 40.8 vs 30.4 at V˙o2max, p = 0.02, asthma; 37.2 vs 35.84 at V˙o2max, p = 0.02,control) and the dyspnea index ( V˙e/MVV) at submaximal(0.44 vs 0.38, p = 0.05, asthma; 0.32 vs 0.38, p < 0.01, control)and maximal exercise (0.72 vs 0.63, p = 0.03, asthma; 0.49 vs 0.62,p = 0.02, control) occurred in the asthma group. Exercise rehabilitation improves aerobicfitness in both asthmatic and nonasthmatic participants of a 10-weekaerobic fitness program. Additional benefits of improved ventilatorycapacity and decreased hyperpnea of exercise occurred in patients withmild asthma.