Ventilatory and heart rate adjustments during submaximal and maximal exercise in patients with chronic obstructive lung disease.

Thirty-four patients with chronic obstructive lung disease were exercised stepwise up to maximal work load. V02 at maximal work load showed a slightly significant correlation to FEV1, while a closer association with VC as well as Ve and Vt was noted. In most patients Vt during maximal exercise was around 50% of VC, while no such limit was present when Vt was related to FEV1. These patterns were independent of the clinical type of obstructive lung disease. At 300 kpm/min (50 W) Vt/VC% as well as heart rate was negatively correlated to V02 max, but not to FEV1. No significant relationship was seen between V02 or Ve at this exercise level and V02 max, as well as FEV1. The ventilatory pattern during exercise seemed to reflect the patients' ventilatory strain more adequately than pre-exercise FEV1. The negative relationship between heart rate during moderate exercise and V02 max might further reflect this strain.