Oxygen supplemented exercise of ventilatory and nonventilatory muscles in pulmonary rehabilitation

An outpatient pulmonary rehabilitation program was evaluated for evidence of patient improvement. All patients exercised on 4 LPM oxygen (O2). Inspiratory resistive loading (ventilatory muscle modality) was prescribed to achieve one-half of the patient's maximal inspiratory force at minute ventilation (VE) not greater than one-and-one half times resting VE. Walking (nonventilatory muscle exercise) was prescribed at work level requiring VE of 50 percent of maximum breathing capacity, if a ventilatory limit to exercise, or a work level set at 60 percent of VO2 maximum, if no ventilatory limit to exercise. Significant improvement was noted after rehabilitation in maximum workload, 12 min walk, and endurance both on room air (RA) and O2, as compared to pre-rehabilitation values. No improvement was noted in resting pulmonary function, gas exchange, exercise-induced hypoxemia or VO2 max. O2 increased work performance compared to values in the same patients on RA, both before and after rehabilitation, an effect possibly mediated by O2-induced reduction in submaximal VE.