Asthma and diving

Asthma is a chronic lung condition in which the muscles surrounding the bronchial tubes (airways) tend to contract excessively. This causes narrowing or constriction of the bronchial tubes (bronchoconstriction), resulting in increased resistance to breathing, particularly during the exhalation phase, and manifested by wheezing, chest tightness, coughing and shortness of breath. Learning about the effects of asthma on diving also includes knowing the effects of asthma medication and diving, and how to determine if you are fit to dive with asthma. This article is a first step in helping the asthmatic diver better understand and manage this chronic disease.
(from DAN Diver's Health magazine)
There are several forms of asthma and when a person suffers from allergic asthma, a medical certificate from a specialist doctor is required for scuba diving.

Our advice:

An asthma attack while diving can have serious or even fatal consequences for the diver underwater. Indeed, an asthma attack causing a resistance to expiration blocks the air in the alveoli which, by dilating excessively during the ascent very often in panic, can rupture causing serious lung lesions.

We strongly advise against diving for chronic asthmatics.