Abstract

Five volunteers, all with a history of childhood asthma that had persisted, performed six treadmill runs on separate days for 6 min at 80 of V02max followed by 20 min of recovery. Two trials were completed under each of the following conditions: normal, positive end-expiratory pressure breathing (PEEP) during the work, and PEEP post-exercise. For each trial, forced vital capacity maneuvers (FVC) were completed twice at rest, at the 3rd and 6th min of exercise and every 5 min during the 20-min recovery. No significant effectsof PEEP on resting pulmonary function values was found nor was PET C02 altered for rest, exercise, or recovery for PEEP vs normal trials. For the normal exercise tests, post-exercise broncho-constriction was shown by a decrease in FEV, a drop in PEF, and a decrease in maximal flow at 50 VC (MEF50), comparing post-exercise values to rest. PEEP during and PEEP post conditions significantly decreased the severity of exercise induced asthma. Since PET C02was not altered by the PEEP conditions, the airway response cannot be mediated through C02 effect. It is known that PEEP does reduce air trapping, but since PEEP during work had a lasting effect into recovery ths indicates some additional mechanism. Verf.-Referat