Asthma And Diving: Asthmatics continue to dive

Asthma and other respiratory diseases that predispose to air trapping have traditionally been seen as absolute contraindications to scuba diving because of the risk that overexpansion of trapped air within the lungs could lead to decompression problems during ascent (‘Demographics and respiratory illness prevalence of sport scuba divers’, Int J Sports Med 2005;26:607-610).

Yet a questionnaire survey of German-speaking recreational scuba divers revealed that nearly one in five suffered from asthma or dyspnoea (shortness of breath) or had a history of other respiratory illness. Between them these apparently unsuitable divers had logged a total of 17,386 dives – with no cases of serious diving injury.

The survey, distributed with the September 2002 issue of the sport diving magazine Tauchen, which has a circulation of about 85,000 divers in Austria, Germany and Switzerland, is believed to be the first to provide comprehensive data on respiratory illness and symptom prevalence in sport scuba divers.

Completed questionnaires were returned by 322 divers – 226 men and 96 women. Of these:

• 8.7% reported that they currently had asthma – of whom two thirds complained about regular breathing difficulties;
• 4.7% suffered from breathing difficulties alone;
• 5% reported a history of respiratory illness other than asthma.

Of the asthmatics, fewer than half used drugs to relieve or control their symptoms regularly. And 63.6% – mostly men – reported maximum depths that were beyond the recommended depth limit for sport diving of 40m.

Because of the limitations of the study – self-reporting coupled with a poor response rate – the researchers do not feel able to conclude that diving for sufferers of respiratory disease in general, and asthma in particular, is safe. Their cautious conclusion is that: ‘there is a subpopulation of scuba divers with chronic respiratory diseases or complaints who may dive uneventfully for years, but may need specialist guidance for managing their disease and understanding the associated risks’.

Isabel Walker is the former editor of Peak Performance