Physiological effects of emphysema may include all of the following, except

Emphysema is a pathological condition of the lungs marked by an abnormal increase in the size of the air spaces, resulting in labored breathing and an increased susceptibility to infection. It can be caused by irreversible expansion of the alveoli or by the destruction of alveolar walls.Ref: Ganong&;s review of medical physiology, 23ed edition page no: 595