The link between exercise, respiratory heat exchange, and the mast cell in bronchial asthma.

There are two apparently conflicting theories on the pathogenesis of exercise-induced asthma. One view is that exercise-induced asthma is directly related to respiratory heat exchange and that mast cells are not involved. The other theory explains exercise-induced asthma on the basis of a temperature-independent release of mast-cell mediators. A theory is put forward here that airway cooling in asthmatic subjects during exercise leads directly to mast-cell degranulation and that this explains the association between exercise, respiratory heat exchange, and mediator release.