[Exercise-induced bronchospasm in asymptomatic asthmatic children. Incidence and characterization of the response in comparison with normal children].

Four-hundred and eighty five asthmatic children and twenty-nine controls underwent exercise challenge consenting of running up and down a flight of stairs over five to eight minutes. An exercise-induced bronchospasm was considered to occur if the FEV1 fell over 15% or the MMEF 25%-75% over 25% from the pre-exercise values. There was an incidence of 38.5% positive responses in asthmatics and none was observed in controls. The peak fall of both flow indexes occurred at five minutes post-exercise. The MMEF 25%-75% was more sensitive in the detection of the EIB. It was noticed a seasonal variation in the incidence of the EIB.