Exercise-Induced Bronchoconstriction: A Frequent, but Neglected Cause of Chest Pain

ramp protocol on a treadmill (ATL, Inbrasport, Brazil). Oxygen uptake (VO 2 ), carbon dioxide (VCO 2 ), and ventilation (VE) were registered every ten seconds using a metabolic cart (Handymet, MDI, Brazil). Forced expiratory volume in one second (FEV1) was measured immediately before the exercise test and in several moments after peak exercise (immediately, 5 minutes, 10 minutes, and 15minutes) (Smart One, MIR, USA). A 12-lead electrocardiogram was continuously recorded (XCribe, Mortara, USA), and non-invasive blood pressure was measured each two-minutes The ventilatory threshold was identified by the combination of the following methods: 3 at the point of the first upward inflection of the ventilation vs. time curve, at the beginning of a consistent increase in the ventilatory equivalent for O2 (minute ventilation/ oxygen consumption) without a concomitant increase in the ventilatory equivalent for carbon dioxide (minute ventilation/carbon dioxide production), and at the beginning of an increase in expired oxygen fraction.