Prevalence of exercise-induced bronchospasm among athletes in the hot and humid climate of Brazzaville, Congo

Background: This study aims to determine the prevalence of EIB in high-level Congolese athletes acclimated to hot and humid air conditions. Materials and Methods: The study involved 18 high-level athletes training in an environment relatively polluted. The stress test consisted of a continuous running treadmill warm-up set at 7.5 km.h-1, followed by an endurance race incremented by 1.5 km.h-1 every 3 minutes until exhaustion. Respiratory function examinations were performed at rest, at the end of the exercise test and at 5-minute increments for 25 minutes. For each modality, the EIB diagnosis was based on an average reduction of at least 10 % in the first-second forced expiratory volume (FEV1). The subjects who presented this criterion were declared sensitive to bronchospasm and constituted the EIB (+) subgroup, while those that were not identified as such were considered non-susceptible and constituted the EIB (-) subgroup. Results: A prevalence of 33 % EIB was observed among athletes. A significant mean post-exercise FEV1 decrease of 18.37 % was observed in EIB (+) compared with EIB (-) individuals. Conclusion: The hyperventilation associated with particulate matter may play a greater role in the initiation and exacerbation of post-exercise bronchospasm in hot, humid climates.