One of the most common questions the Divers Alert Network (DAN) receives on a regular basis is whether or not a person with asthma can dive. Specific questions center on the reasons why asthma may cause problems for a person when diving. Since people with asthma have traditionally been excluded from diving, it is good to know that this is an issue that has been brought to the forefront in the diving industry and that it has gained a lot of recognition. There are very different guidelines and rules for diving with asthma, depending on where you go in the world. The most relaxed guidelines can be found in the UK: a person may dive if they have not needed their inhaler within 48 hours prior to the dive and as long as they do not have asthma that is triggered by cold, exercise, or emotions. However, the opposite is found in Australia, where the strictest rules are implemented. In Australia, a person cannot even become certified without passing a spirometry test, otherwise known as a lung function test.
So what does diving with asthma really mean? What are the reasons why diving with asthma can cause problems? Well, first let's look at what asthma is. It is a disease of the lungs in which the airways can become restricted so that a decreased amount of air can travel in and out of the lungs. This can potentially cause two problems. One of these is that the diver already has restricted breathing due to the breathing apparatus that must be used. With the potential of an asthma attack on top of the restricted breathing there comes a decrease in exercise capacity, which can seriously impede a diver. The second problem is that because the airways become narrowed and blocked, gas can become trapped in them on ascent and this can result in lung rupture if the gas expands faster than it can be exhaled. A lung rupture can result in arterial gas embolism and/or a collapsed lung.
In addition to these very real concerns of diving with asthma is the fact that the conditions in which the dive takes place may very well bring on an asthma attack. These conditions include the breathing in of cold, dry air and the potential inhalation of cold sea water, which can happen if there is a leak in the regulator or if the mouthpiece falls out. With a potentially decreased exercise capacity, this can put asthmatics at great risk when diving. When exercising on land, people with asthma can stop when they feel they need to, but when diving this may not be an option and this can lead to a dangerous situation and even to death.
At this point there are no clear guidelines to go by when considering whether or not to dive if you have asthma. It has been suggested that there are a number of people with mild asthma who have been diving safely and that people with the three more mild cases of asthma – mild, intermittent, or mild-moderate – may be safe to dive if their asthma is well controlled. DAN is working on a set of universal guidelines regarding diving with asthma and as such is trying to collect information on diving and asthma, which is severely lacking at this point in time.
Two assessment questions must be posed when considering whether someone with asthma can dive and these are:
- Is the asthma mild?
- Is the treatment working well enough to prevent an acute asthma attack while underwater or on the surface of the water?
At this point, while the jury is still out on the matter, the best person to consult with if you have asthma and are considering diving is your physician. You should have a lung function test and an exercise test in order to determine the severity of your asthma. Seeing a physician who has experience with both asthma and diving is a plus. Considerations will include the severity of the asthma, what triggers an asthma attack, and the person's history of asthma attacks. Your overall level of health and fitness will also be a determining factor when it comes to making a decision on diving with asthma. You might find that you go through all the testing and have the backing of your doctor and still are not allowed to dive in some areas. For now you may have to live with this and know that things are slowly changing for the better. If you do dive, be sure that your dive leader and your dive buddy are aware that you have asthma and of what to do should an asthma attack happen while you are underwater. Then you can take the plunge and enjoy the sport you love.