Effects of Altered Airway Function on Exercise Ventilation in Asthmatic Adults

• Published in: Medicine and science in sports and exercise 2014-06, Vol.46 (6), p.1104-1113
• Main Authors: ROSSMAN, MATTHEW J, NADER, SUSAN, BERRY, DUSTIN, ORSINI, FRANCESCA, KLANSKY, ANDREW, HAVERKAMP, HANS CHRISTIAN
• Format: Article
• Language: English
• Subjects: Adolescent; Adrenergic beta-2 Receptor Agonists - therapeutic use; Adult; Asthma - drug therapy; Asthma - physiopathology; Biological and medical sciences; Bronchoconstriction; Bronchodilator Agents - therapeutic use; Chronic obstructive pulmonary disease, asthma; Exercise - physiology; Exercise Test; Female; Forced Expiratory Volume - physiology; Fundamental and applied biological sciences. Psychology; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Maximal Midexpiratory Flow Rate; Medical sciences; Peak Expiratory Flow Rate; Pneumology; Pulmonary Ventilation - physiology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Vital Capacity; Young Adult
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1249/MSS.0000000000000206

PURPOSEVariable airway function is a central feature of the asthmatic condition. Thus, habitually active asthmatics are certain to exercise under conditions of variable airway (dys)function. The purpose of this study was to determine the effects of variable preexercise airway function on ventilation during whole-body exercise in asthmatic adults. METHODSEight mild asthmatic (age = 26 yr; V˙O2peak = 49 mL·kg·min) and nine nonasthmatic (age = 30 yr; V˙O2peak = 46 mL·kg·min) adults performed constant workrate cycling exercise to exhaustion after four separate interventions1) a control trial (CON); 2) inhalation of fast-acting β2-agonist (BD); 3) eucapnic voluntary hyperpnea challenge (BC); and 4) sham to the hyperpnea (SHAM). Pulmonary function was assessed at baseline and after each intervention. Exercise ventilation and operating lung volumes were compared among the four exercise trials in both control and asthmatic subjects. RESULTSBaseline pulmonary function was significantly lower in asthmatic subjects compared with control subjects. In asthmatic subjects, postintervention (i.e., preexercise) forced expiratory volume 1.0 s was significantly different among the four exercise trials (CON = 3.5 ± 0.4, BD = 4.1 ± 0.4, SHAM = 3.6 ± 0.3, BC = 2.8 ± 0.3 L, P < 0.05), whereas it was not different in control subjects. There were no differences in exercise ventilation or operating lung volumes during exercise among the four trials either within asthmatic subjects or between control and asthmatic subjects. CONCLUSIONSThese findings suggest that the state of airway function—whether bronchodilated or bronchoconstricted—before exercise in the mild asthmatic does not affect the exercise ventilatory response. Thus, ventilatory system function in the asthmatic appears to be responsive to the acute requirement for increased airflow during whole-body exercise.