Background It is known that the pulmonary function shows a decline over time. There is the potential for an increase of airway damage among athletes who have higher ventilation compared with normal population. This means that the athletes with BA are suffering the doubled risk of airway damage due to their chronic inflammation of asthma and hyperventilation by sport.

Objective The purpose of this study is to investigate if higher ventilation over time causes airway damage among athletes and the adequate treatment for BA prevents unnecessary airway damage.

Design A retrospective study.

Setting Elite athletes, Olympic team.

Main outcome measurement 88 athletes older than 18 years old who participated both Beijing (2008) and London (2012) Olympic Games and underwent spirometry were included in this study. Spirometry measurements of athletes were collected at the pre-competition medical assessment before Beijing and London Olympic Games. The change in the values of spirometry parameters over four years was compared with its predictive values to verify if sports affect athlete's pulmonary function. Athletes were categorized into 4 groups depending on past history, present illness and treatment history of BA.

Results Athletes who had a past history of BA have a tendency for the worse value than the predictive value in FEV₁(forced expiratory volume in one second). However the change of value over four years has not shown significant difference. The other hand, asthmatic athletes who have an adequate treatment have not shown a different value to predictive values and the value did not show any chorological change over four years.

Conclusion The decline of pulmonary function over time was found in athletes. Our study suggests that exercise may not affect the aggravation of obstructive abnormality on asthmatic athletes with a proper treatment for BA.