Asthma and Freediving

Asthma and Freediving

Instructor course handout

Cristian Castaño Villa

Asthma is a chronic long term disease that affects the airways through inflaming and narrowing, making the process of breathing (bringing air into and out of the lungs) very difficult. Asthma then develops with symptoms such as coughing, wheezing (whistling sound when you breath), shortness of breath and chest tightness. The coughing generally occurs at night or early in the morning. These symptoms can develop into what is known as an asthma attack that can be controlled by bronchodilators (substances that open the airways) like salbutamol, ipratropium bromide, or in extreme cases adrenaline. In some cases, these attacks can be extremely serious requiring intubation (a tube down into the lungs) and artificial ventilation, leading to hospitalization.

The airways or air passages are tubes that carry air in and out of our lungs. People with asthma have inflamed and swollen airways, making this process very difficult or in extreme cases, impossible. The airways in an asthmatic are sensitive to certain substances such as dust or pollen. The muscles around the airways temporarily tighten, and substances in the air can also exacerbate mucus, therefore triggering the symptoms of asthma and thus reducing air flow in or out of the lungs. The symptoms can occur anytime the airways are inflamed. When these symptoms increase it’s called an asthma attack, asthma attacks are also known as exacerbations or flareups.

The prevalence of Asthma is increasing however as yet, there is no cure. There are treatments to reduce the symptoms and for some these treatments are highly effective. If you have asthma and it is well treated, normal life can be lived, however, if not then it can lead to multiple visits to the hospital, affecting your normal life at home and work and in extreme cases, the disease can even be fatal.

Types of asthma

There are different types of asthma that affect people in different ways. Medical advances have given us a better understanding of the different types of asthma and their causes. So in order to find the solution or the best treatment for the disease we need to understand what causes or triggers it. The following are the different asthma types:

Allergic Asthma: This is the most common type of asthma, and is caused by external agents. It can be triggered by something as minor as a smell, such as perfume or cleaning agents. Other triggers include pollen, dust, mites, mould and cold air. A trigger can be different for everyone, so it is important for an asthmatic to know their personal triggers, although in some cases the triggers are difficult to identify because the allergic reaction can take days to fully develop. Allergic rhinitis, also called hay fever, is the most common allergic disease. It creates inflammation of the inside lining of the nose. An allergy to a substance causes your body to react against it by activating immune cells. These cells release histamines which come into contact with the allergens, however, these histamines and other chemicals can produce the allergic symptoms which we commonly see when an allergic reaction happens such as running nose, ongoing sneezing, swollen nasal passages, excess mucus, weepy eyes, scratchy throat and cough.

Exercise-Induced Asthma: This is the type of asthma that is induced by strenuous exercise or physical exertion, almost every person who has asthma can be triggered just by exercising. Asthma symptoms can be experienced by non-asthmatic people temporarily while doing intense exercise. The peak of exercise-induced asthma can be reached at 20 minutes of performing a sport, making it very difficult to breathe. The symptoms in both asthmatic and non-asthmatic people can be shortness of breath, wheezing and coughing. These symptoms can be controlled by using an asthma inhaler or bronchodilator. Exercise-induced asthma it’s also called bronchoconstriction. For most, preventive measures and normal asthma medications are sufficient to allow them to continue doing exercise and remain physically active.

Cough-Variant Asthma (CVA): Dry severe coughing is the main and strongest symptom of this form of asthma. This condition is commonly underdiagnosed and undertreated as there are also other causes of coughing when you have asthma, like postnasal drip, chronic rhinitis, or sinusitis. The main causes of CVA are usually respiratory infections and exercise. People who have CVA do not necessarily have the other common symptoms of asthma, like wheezing, shortness of breath or chest tightness. One characteristic of CVA is that the cough does not produce mucus from the respiratory tract.

Occupational Asthma occurs in the workplace, where triggers are the results of the workplace environment. The symptoms are a runny nose, congestion, eye irritation and coughing instead of wheezing. Certain occupations have a higher propensity to cause this kind of asthma, such as animal breeders, farmers, painters, hairdressers, nurses and woodworkers. This form of asthma can be caused by inhaling fumes, gases, dust or other potentially harmful substances.

Nighttime (Nocturnal) Asthma: is one of the most common types of the disease and can give the strongest symptoms. This happens because asthma is influenced by the sleep-wake cycle (circadian rhythms). Symptoms such as trouble breathing, coughing or wheezing are more likely to manifest and be more dangerous at night. Most deaths related to asthma occur at late hours due to changes in air temperature, the reclining position of the body, as well as the hormonal releases from the body that follow a circadian pattern.

Other health conditions similar to asthma: There are some other illnesses that can mimic the symptoms of asthma, for example, cardiac asthma is a form of heart failure, or vocal cord dysfunction is a disease that can be mistaken for asthma because the abnormality of the vocal cords could cause wheezing. Furthermore, anxiety and stress can be diagnosed as asthma because of similar sensations such as tightness in the chest and breathlessness. In order to check if a person actually has asthma a spirometry test (a test that measures your vital capacity) or a peak flow test (a test that measures how fast you can breathe out) can be performed.

Scuba diving and asthma

Recreational diving with self-contained underwater breathing apparatus (scuba) is not recommended for people suffering from asthma as breathing compressed air could trigger an asthma attack. Also, depending on the type of asthma the person has, such as exercise-induced asthma, the chances of an attack happening can increase considerably.

While diving, an asthmatic could be exposed to environmental factors like aspiration of salt water, inhalation of aerosolized hypertonic saline from faulty regulators, or in rare cases, contamination of the air tank through the use of non-filtered air containing pollens. Any of the above situations could increase the risk of bronchospasm leading to an acute asthma attack as well as panic attacks or drowning.

The biggest concern with asthmatics diving is that they are more likely to suffer dive related illnesses such as embolism, which is when bubbles of air get into the blood due to damaged lung tissue. This scenario could also happen by the narrowing of the airways in an asthmatic diver. Furthermore, the use of asthma medication could cause the lungs to be less efficient at filtering the nitrogen bubbles that happen after diving, resulting in a risk of decompression sickness. When evaluating a diver candidate many factors should be considered, such as; how bad asthma the person has, what type of asthma it is, how often they have asthmatic episodes or how long ago was their last asthma attack. Each asthmatic candidate should be assessed individually, evaluating their asthma history and severity.

Several published guidelines include the recommendation that asthmatic people should be prevented from diving in the following circumstances; subjects with tremendous airway variability which could worsen without reason, those with poorly defined triggers and abnormal pulmonary function tests and asthmatics with exercise, cold or emotional induced asthma, other experts are more conservative suggesting that any person with asthma symptoms in the preceding 5 years should be advised against diving.

Reasons why people with asthma should not freedive

Freediving is an extreme sport which demands both physical and mental energy and effort and for this reason many of the above reasons opposing asthmatics to scuba, also apply to freediving. Similar environmental factors can also affect the freediver as in scuba due to the risks, such as; aspiration of salty water, dust that could be expelled from the boat engines, or other cells in the air could set off an asthma attack. An important factor to keep in mind if the diver has any variety of asthma is that it can make it much harder to perform rescue and resuscitation in the case of emergency. If the diver experiences a lung squeeze and/or blackout, the blood could act as a trigger and make the airways further constrict, making any attempt of resuscitation by ventilating the person externally very difficult or impossible.

It is believed the risk of having a lung squeeze could increase in people with asthma. Certain asthmatics, even if breathing normally and feeling well, could have excess mucus in the airways or some low-level inflammation, and this could mean higher chances of a squeeze happening with high levels of hypoxia. Also, the chances of air embolism are increased. This is due to the narrowing of the airways and little bubbles of air can become trapped, expanding on the way up due to Boyle’s law and then finding their way into the bloodstream. There’s also a risk that a mediastinal rupture can happen, also because of Boyle’s law, when the trapped air squeezes out of the lungs and goes to the space around heart, trachea and oesophagus, causing a lot of pain. Another issue that could occur is when experienced freedivers go to depths below 30m and their lungs compress below residual volume, this could act as a trigger in the asthmatic, and cause difficulty in recovery breathing or increased risk of a blackout.

As for scuba diving, there are some strong reasons why asthmatics should avoid or be especially careful when practising freediving, however it is also important to note that every case should be evaluated individually in order to decide if the person is fit or not to practice the sport.

Reasons why people with asthma should freedive

Just as there are similarities in the reasons why people shouldn’t scuba dive when they have asthma and why shouldn’t they freedive, there are also reasons to the contrary. Freediving does not involve breathing compressed air underwater, as freediving is performed using one single breath at the surface, and so the risks of compressed air as trigger to asthmatics is eliminated. Furthermore, an asthma attack during a scuba dive is more dangerous due to the requirement of the safety stop, while in freediving there’s no safety stop, and so in the case of an asthma attack the person can return immediately to the surface.

Just as medications can’t cure asthma only reduce the symptoms and severity, freediving has also not cured asthma. However, there are many cases of asthmatic freedivers drastically reducing their medication, as well as symptoms and attacks to the point of being symptom free. Examples of this are; the Dutch freediver Peter Wurschy who, after suffering from a lung infection that gave him severe asthma attacks, could manage to be completely free of symptoms after three years, and French freediver Florian Dagoury, who claimed to have reduced his asthma by 50% and hasn’t returned to the hospital, whereas previously he visited the hospital at least once a year before discovering freediving.

It has been proven that there are many benefits to slow, calm breathing in patients with asthma, and that is the foundation of breathing in freediving. When you breathe slowly and controlled you can increase the amount of carbon dioxide in both your lungs and blood vessels, and its effect is to expand the blood vessels which is beneficial. Carbon dioxide has the effect of naturally recalibrating the control centre of the breathing in the brain, thereby restarting normal breathing for people with asthma. Particular breathing techniques can assist this process such as hook recovery breathing. When we do hook breathing we hold our breath and then push the air out using our diaphragm and abdominal muscles, this increases the pressure in the lungs and the increased pressure in the lungs helps to dilate the airways, so it’s a natural way to help an asthma attack without the need for medications. There’s another gas molecule that helps to relax and dilate the blood vessels and that is called nitrogen oxide (NO), this molecule accumulates in our nostrils and sinuses, and by doing equalisation manoeuvres and holding the air for 20 – 30 seconds in our sinuses and nose (as in mouth-fill or constant equalisation), then it can be dragged to the lungs helping to dilate the blood vessels.

Practising freediving regularly provides more flexibility in the lungs, diaphragm, muscles and organs in the body and this can also assist to relieve tension and stiffness experienced with asthma attacks. The airways gain more flexibility through practising freediving, yoga and pranayama breathing, by allowing more air to flow in and out of the lungs even during an asthma attack.

In conclusion, freediving could definitely assist the asthmatic as long as they practice it within the safety limits and risk assessment, by being careful and responsible considering the type of asthma they have. While freediving may not cure asthma it could provide relieve of the symptoms in the long run.


  • Asthma is a chronic lung disease that affects a large part of the world’s population, it’s a growing disease which, as of yet, has no cure.

  • There are different types of asthma, not all of them should be treated the same, some affect people more when freediving than others.

  • People with asthma have often been discouraged from scuba diving, mainly because of the compressed air inhaled during scuba and this can be an asthma trigger. This principle does not apply to freediving.

  • Exercise-induced asthma could be a reason to discourage a person from freediving because while freediving it’s possible to reach the point of strenuous exercise or physical exertion that can lead to an asthma attack.

  • Performing a rescue in a person with any type of asthma could be more difficult in the case that the airways constrict, making it very hard to resuscitate or ventilate the person.

  • The chances of a lung squeeze, embolism or mediastinal rupture are higher in people with asthma.

  • Calm, slow breathing increases the amount of carbon dioxide in both the lungs and blood vessels, and carbon dioxide has the effect to expand the blood vessels which is beneficial for people with asthma.

  • Carbon dioxide has the effect of naturally recalibrating the control centre of the breathing in the brain, re establishing normal breathing for people with asthma.

  • Hook breathing increases the pressure in the lungs, and the increased pressure in the lungs helps to dilate the airways.

  • Nitrogen oxide (NO) has also the effect of dilating the blood vessels, and we can increase the levels of NO in our lungs when we equalise.

  • More flexibility in the lungs, diaphragm and airways can help to lower the intensity of an asthma attack.

  • Every case of a person with asthma should be analysed and evaluated individually in order to decide if the person is fit or not to practice freediving.

  • Freediving will not cure asthma but in the long term, it can help to reduce the medications a person has to use, as well as frequency of asthma attacks and hospital visits, thus leading to a better life.

  • For almost any patient with lung disease, the main medical recommendations are, calm, slow breathing, physical training and no smoking. All of this is part of a healthy freediving lifestyle.


  • Avall Severinsen, Stig. Breathology: The art of conscious breathing. N.p.: BlueConsult, 2010.

  • Adir Yochai, and A. Bove, Alfred. «Can asthmatics subjects dive?» Sport-related lung disease. 24 Mar. 2016.

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