Definition of EIB
Exercise-induced bronchoconstriction is defined as acute narrowing of the respiratory tract that occurs as a consequence to physical effort. This condition occurs both transiently and reversibly , which means that in a few minutes after physical effort, the condition of the airways returns to the state before exercise. EIB can occur both during and after exercise, and can be manifested by coughing, chest tightness, shortness of breath and wheezing. The greatest reduction of airflow usually occurs approximately 10 to 15 minutes after the start of exercise and may last up to 30 to 60 minutes before resolving. A relative refractory period is also observed, and the repetition of exercise within 60 minutes of the original symptom usually causes recurrence of bronchoconstriction6.
Furthermore, this condition can be observed both among healthy patients, especially those performing strenuous physical activity, and those suffering from asthma7. For this reason, some researchers suggest that EIA and EIB are synonyms8. Others have stated that EIA occurs only in asthma-diagnosed patients, while EIB appears exclusively in those who do not present symptoms of asthma9,10.
The question has been raised by some researchers, whether the number of patients suffering from EIB is underestimated and whether many such athletes remain undiagnosed or untreated11. Our findings suggest that reduced awareness of symptoms of early adolescents significantly hinders diagnosis of EIB. Dickinson J et al. state that only 59% of athletes diagnosed with EIB reported at least one symptom. Other reasons why athletes do not report their symptoms may include concern over losing status in their team or showing “signs of weakness”12. Furthermore, athletes may not recognize symptoms of EIB and misinterpret breathing difficulties as a normal part of their physical training. It is also worth noting the variety of EIB symptoms, as in some athletes normal results of respiratory tests are connected with signs of EIB. This finding is related to study by Rundell et al., who suggested that symptoms reported by athletes are not related to the presence of bronchospasm. The proper diagnosis should be based on accurate patient history, spirometry and an exercise challenge test. Many physicians treat EIB only on the basis on symptoms, without performing a standardized exercise test13.