Although regular exercise improves asthma control in adults as measured by the Asthma Control Test (ACT), it has little effect on peak expiratory flow (PEF) variability, according to a study published in Scientific Reports.

What limits expiratory flow?

Minute Volume of Ventilation

Maximal expiratory flow rate is limited by flow-dependent airway closure (page 38), and is relatively unaffected by training. However, within the limits of MBC, it is possible to increase the strength and endurance of the respiratory muscles.

Does exercise affect lung compliance?

Pulmonary compliance remained unchanged during exercise. Nonelastic resistance showed an insignificant increase (0.9—1.4 cm H2O per liter per sec). Examination of other parameters which may affect compliance were made.