The Place of Physical Exercise and Bronchodilator Drugs in the Assessment of the Asthmatic Child.

Among the many factors that affect ventilatory function in the asthmatic subject, physical exercise and bronchodilator drugs are two of the more important. It has been shown that physical exercise has two distinct and opposite effects on ventilatory function depending upon the duration and level of exercise (Jones, Buston and Wharton, 1962). Providing the level is adequate, exercise lasting less than two minutes increases the forced expiratory volume in one second (F.E.V.), whereas exercise lasting eight to 10 minutes produces a fall of F.E.V. following and sometimes also during the exercise. In this paper we describe the clinical implications of these effects of exercise and their modification by bronchodilator drugs.