To test the hypothesis that declining ventilatory function in the elderly impairs exercise capacity, we tested maximal exercise capacity and ventilatory function before and after a program of ventilatory muscle training in 25 elderly subjects (ages 65-75 yr). Ventilatory muscle training was performed by means of isocapnic hyperpnea for 30 min/day, 4 days/wk for 8 wk. Before and after the training, we measured maximal exercise capacity by means of an incremental exercise test (IET) and ventilatory muscle endurance by means of the maximum sustained ventilatory capacity (MSVC). Ratings of perceived exercise (RPE) for breathlessness and leg effort were evaluated each minute by means of a modified Borg scale during both the IET and a 12-min single-stage exercise test (SST) performed at ~ 70% of the maximal exercise capacity. The trained group showed a significant increase in the MSVC, from 71.9 ± 26.4 to 86.9 ± 20.9 l/min (P < 0.01), whereas the control group showed no change (66.3 ± 22.5 to 65.1 ± 22.1 l/min). In addition, the maximal voluntary ventilation increased in the trained group, from 115 ± 41 to 135 ± 36 l/min (P < 0.01). Neither the trained nor the control group showed an increase in maximum O2 uptake, maximum CO2 consumption, or maximum minute ventilation during the IET. Evaluation of the RPE during both the IET and SST showed that although there was a small decrease in RPE for breathing and leg discomfort, changes between the control and treated groups were similar. We conclude that 1) ventilatory muscle training improves the MSVC and MVV in normal elderly subjects, 2) maximal exercise capacity and RPE during incremental and steady-state exercise are not improved by ventilatory muscle training, and 3) exercise capacity in the normal elderly is probably not limited by impaired ventilatory mechanics.
ASJC Scopus subject areas
- Physiology (medical)