Bradley Wiggins' medical exemptions for otherwise banned substances came under the spotlight over the weekend, as it was revealed he had taken a number of drugs for known asthma and respiratory problems.
However, Wiggins is just one of a number of athletes to be named by hacking group Fancy Bears, which has been leaking certification for theraputic use exemptions (TUE) for banned substances granted by the World Anti Doping-Agency (Wada).
The records leaked by Fancy Bears show a high number of athletes granted TUEs for asthma treatment. But asthma is not a condition widely associated with elite sportspeople, given that physical activity is often cited as a trigger for asthma attacks, which affect the respiratory system, leading to some suspicion about the drugs administered.
However, a 2014 study carried out by Dr John Dickinson, a leading expert on asthma in sport at the University of Kent, found that members of Team Sky – the British cycling squad – were three times as likely to suffer from the condition than the wider population, while 70% of swimmers tested suffered from forms of asthma.
Research carried out by Dr Dickinson suggests those sports with sustained "high-minute ventilations" or heavy breathing.
According to Asthma UK, attacks can be triggered by exercise as exertion tends to cause people to breathe faster and in through your mouth. The changes to the humidity and temperature of air caused by this can lead to a narrowing of the airwaves in asthma sufferers who are more sensitive to this.
There could potentially be a number of causes of exercise-induced asthma, though the non-profit organisation the Mayo Clinic states exercise can cause inflammation and the production of mucus in the airwaves. With this type of asthma of which symptoms are only experienced during exercise, and not at other times. These symptoms are usually most intense after exercising, according to Asthma UK, the treatment is, however, the same.
Speaking about the leaks to the Telegraph, Dr Dickinson said: "There is a lack of education on why athletes develop asthma. People do not understand that medicating against it helps them to maintain an equal playing field — but doesn't increase their advantage."
The issue, says Dickinson, is where athletes take supertherapeutic doses, begging the question as to whether or not they should be competing in the first place.
But, Dickinson said: "At a higher level, people need to be educated so that they understand that asthma medication doesn't give you super lungs. Does an athlete using an inhaler have an advantage over me? Based on my research, the answer is clearly no. "