Abstract

Arterial oxygen (Pa02) and carbon dioxide (PaC02) tensions and inspired minuteventilation were measured during the first 2 min of stair-climbing exercise innine normal subjects. The subjects climbed a staircase at a rate of approximately 9m vertical height every minute and arterial blood was drawn from an indwelling cannula at 15-s intervals. Large falls in Pa02 from a resting valueof 92 +/- 2.0 (mean +/- SE) Torr to a lowest value of 65 +/- 3.4 Torr were recorded in the first 50 s of exercise while PaC02 oscillated around the resting value. Most subjects demonstrated an initial plateau of Pa02 for at least 7 s followed by a rapid fall and subsequent rise toward the resting level after 1 min. The falls in Pa02 measured were larger than those reported for laboratory exercise. The possible reasons for this discrepancy are discussed. Verf.-Referat