Why do so many top pros have asthma?
As Chris Froome’s salbutamol case rumbles on, Cyclist looks at whether asthma really is common among elite athletes, or if it’s a smokescreen for something more shady
Surely asthma sufferers don’t make top endurance athletes? No, but the truth is there are plenty of reasons why cycling leads to asthma. ‘Research indicates that exercise-induced asthma may be up to five times more common in Olympians than in the general population,’ says Dr James Hull, consultant respiratory physician at the Royal Brompton Hospital and an authority on asthma in sports medicine.
Asthma is an inflammation and irritation of the air passages in the lungs that causes difficulty in breathing. It’s a serious condition that killed 1,300 people in the UK last year.
While some people grow up with what may be termed ‘general’ asthma, others encounter it during periods of intense respiratory strain. The latter is often called ‘exercise-induced asthma’, although Hull suggests it should be named differently: ‘As 90% of all asthmatics are triggered when exercising, I prefer the term “sport asthma” when referring to the symptoms experienced by elite athletes.’
If riders such as Froome and Wiggins are genuinely asthmatic, what’s the problem?
‘Cynics suggest athletes are faking symptoms to take asthma medication,’ says Dr Jarrad Van Zuydam, physician for Team Dimension Data. While many treatments actually offer no competitive advantage, more serious conditions (including ‘sport asthma’) may require medication that’s strong enough to offer some advantage to the athlete using it.
What kind of advantages?
Asthma can be treated with corticosteroids, which in some cases can increase energy and improve recovery. Pro riders need a Therapeutic Use Exemption (TUE) to use them, and it’s the job of the World Anti-doping Agency (WADA) to ensure the TUE request is genuine.
‘We want to make sure a provocation test and proper physiology variables are provided to us, so we can ensure proper asthma diagnosis has been established,’ says Dr Olivier Rabin, head of science at WADA.
What does this test involve?
‘We need to challenge the athlete in some way to bring about their symptoms,’ says Van Zuydam. ‘This can be done using chemicals [such as methacholine] or exercise.’
First a baseline spirometry test measures lung volume and expiration velocity. Then the lungs are tested during exercise. ‘Athletes exercise at 85% of their maximum heart rate for at least four minutes before undergoing a second reading. A drop of 10% or more of a measure called FEV1 is considered diagnostic.’
The result may warrant a daily ‘preventer’ inhaler of corticosteroids.
Is that what Froome took?
No. Froome took salbutamol, more commonly known as Ventolin and seen in a blue inhaler. Salbutamol is a bronchodilator that relaxes the muscles in the airways, helping to relieve symptoms of asthma but not treating it.
‘There are a great number of studies now that indicate that, when taken at normal prescribed doses, inhaled salbutamol does not benefit athletic performance,’ says Hull.
Rabin at WADA agrees: ‘We’re not going to request a provocation test for every single athlete on a salbutamol prescription. We know that taking salbutamol inhalation of 800mg per 12 hours is not performance-enhancing.’
So why is Froome facing a potential ban?
WADA only allows a maximum salbutamol dosage of 800 micrograms per 12 hours (or eight puffs), which Froome’s post-race blood test suggests he exceeded.
‘We have an upper limit because we have multiple publications showing that systemic use of beta-2 antagonists [bronchodilators] including salbutamol can be performanceenhancing – they can be anabolic agents if taken by systemic routes,’ says Rabin.
‘Systemic routes’ means injection or ingestion of a pill, but not an inhaler. These publications also rely on studies involving rats, not humans. WADA sets the upper limit on salbutamol, then, to discourage athletes experimenting with, say, injecting salbutamol for its anabolic muscle-growing properties.
The upper limit is also in line with the maximum dosages recommended by pharmaceutical companies. Those are in place not to prevent athletes cheating, but to discourage the use of excessive amounts of salbutamol to manage asthma when a more powerful treatment is required.
To prevent a ban, Froome has to prove that his adverse analytical finding could have been brought on by a legal dose of salbutamol.
Wouldn’t it be simpler to get rid of TUES?
‘I do feel that the process of applying for and being granted a TUE needs to be more transparent to reduce the risk of a TUE being abused,’ says Van Zuydam. Others have suggested that TUES be removed entirely and that riders who are sick simply shouldn’t race, but that might be a little short-sighted.
‘My main concern is that if a team doctor or coach chooses to keep an athlete struggling with asthma in a competition by using a strategy that avoids a TUE, then that athlete’s health may be at increased risk,’ argues Hull.
In other words, an asthma attack at the top of Alpe d’huez could have severe consequences and those consequences may well be far worse for the sport than, for instance, cycling’s greatest star being banned for over-using asthma medication.
‘When taken at normal prescribed doses, inhaled salbutamol does not benefit athletic performance’