Effect of breathing pattern on dead space ventilation VD/VT during exercise.
In order to assess the effect of breathing pattern on measurements of dead space ventilation (VD/VT) during exercise, we studied 6 patients with the complaint of exertional dyspnea. They had essentially normal resting pulmonary function studies and the only abnormality noted during an initial exercise study was an elevated VD/VT associated with a rapid respiratory rate. A second exercise study was then performed during which they were coached to breathe at a slower rate and larger tidal volume. During the exercise study with coaching, the VD/VT response was normal. We conclude that breathing pattern during exercise influences VD/VT and that an increase in total minute ventilation which is accomplished by a preferential increase in respiratory rate may result in an abnormally high VD/VT.
D000368:Aged; D004417:Dyspnea / Q000503:physiopathology*; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000503:physiopathology; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange; D012119:Respiration; D012126:Respiratory Dead Space; D013990:Tidal Volume; D014797:Vital Capacity