Exercise can take your breath away – for all the wrong reasons

The current women's marathon world record of 2:15:25 was set by Paula Radcliffe at the 2003 London Marathon. Radcliffe was diagnosed with asthma at the age of 14. Asthma is a chronic lung condition, and the Asthma Society of Ireland (asthma.ie) states that more than 470,000 adults and children are affected in Ireland, making its prevalence the fourth-highest in the world.

However, there is another respiratory condition which is especially prevalent among those undertaking endurance exercise such as cross-country skiing, swimming and long-distance running, although it need not prevent participation and the pursuit of success in these, and related, activities. Exercise-induced bronchorestriction (EIB) is the transient narrowing of the lower airways following exercise in the presence or absence of asthma. According to a paper published in the British Medical Journal (January 13th, 2016), in EIB, bronchoconstriction typically develops within 15 minutes of starting exercise and usually resolves within an hour or so.

Although EIB is more likely to occur in people with asthma, it can also be found in people without asthma, and the BMJ authors make a further important point: “The term ‘exercise-induced bronchoconstriction’ is preferred to that of ‘exercise-induced asthma’ since asthma is a chronic condition which is not induced by a single bout of exercise.”

Symptoms

Symptoms of EIB include wheezing or shortness of breath; decreased endurance; chest tightness; cough; upset stomach and sore throat. EIB is typically triggered by high-intensity aerobic exercise, and a high ventilation rate (more than 85 per cent of maximum voluntary ventilation). As a result, there is an intense exchange of heat and moisture in the airways and, as mouth-breathing increases during exercise, more allergens and pollutants, including particulate matter, will penetrate into the lower airways. EIB can be exacerbated by cold, dry environments, with reduced moisture content in the lining of the lungs provoking the release of inflammatory chemicals, leading to smooth muscle contraction and bronchorestriction.

Runners, for example, who wish to mitigate the effects of both asthma and EIB on their performance should undertake a proper warm-up before a training run or race. As Paula Radcliffe told Asthma UK (iti.ms/2gpYsPO) : "It was very important to warm up gently over 45 minutes before I competed. I always jogged at a gentle pace for about 10-15 minutes before a race and did lots of stretching, especially in cold weather."

And in the journal Medicine & Science in Sports & Exercise, Canadian researchers considered the "Effect of Warm-Up Exercise on Exercise-Induced Bronchoconstriction". They concluded: "The most consistent and effective attenuation of EIB was observed with high-intensity interval and variable intensity pre-exercise warm-ups. These findings indicate that an appropriate warm-up strategy that includes at least some high-intensity exercise may be a short-term non-pharmacological strategy to reducing EIB."

But how common is EIB in athletes compared to non-athletes? Dubai-based Dr Ramzy Ross is a renowned applied physiology and sports science consultant from First Performance Consultancy (firstperformanceconsultancy.com), and he told The Irish Times: "According to the evidence, EIB seems to be more common in elite athletes, in comparison to their non-athletic counterparts, and seems to be more prevalent by up to around 20% in those who compete in events with an endurance element to them such as cycling, triathlon and rowing. Interestingly, in regards to those non-elites out there, there has been some evidence to suggest physical inactivity as being a risk factor for asthma where bronchoconstriction is triggered via exercise, and that being more active may help reduce the risk of developing asthma, particularly in children."

And last year a European study published in the journal Respiratory Medicine compared asthma risk among 1,568 members of the public with 546 elite athletes. It concluded: "[P]ractice of very high endurance sports and aquatic sports may be associated with increased risks of asthma among athletes. The excess risk is possibly attributed to high frequency of repeated physical strain and excessive ventilation and exposure to allergens and irritants in swimming pools, respectively."

Those concerned that they may have EIB or asthma should see their GP. Similarly, the pharmacological treatment of these conditions is for medical professionals. Elite athletes, however, who are taking inhaled medication for EIB or asthma and related conditions, need to be aware of guidelines and regulations from the World Anti-Doping Agency.

It is also important that coaches, trainers and team doctors who care for competitive athletes with asthma or EIB should have appropriate training in both the recognition and treatment of EIB. And finally, for those who think that having EIB or asthma might somehow place them at a competitive disadvantage compared to their peers, last year an article in the British Journal of Sports Medicine stated: "Contrary to expectations, asthmatic athletes tend to be more successful at major sporting events compared to non-asthmatic athletes. For example, only 17 per cent of the cyclists competing in the 2008 Olympics were asthmatic, but this group won 29 per cent of the individual medals."