Pulmonary limitations to exercise performance: The effects of healthy ageing and COPD

Physiological limitation to exercise performance in health and disease is a complex phenomenon. We simplify our approach to this problem by first defining exercise capacity objectively as the VO₂ max, or that level of oxygen consumption obtained as work rate is gradually incremented to the point where VO₂ no longer increases linearly with further increases in work rate. VO₂ max often correlates quite well with endurance exercise performance. However, there are exceptions to this tight correspondence; for example, with physical training in which endurance performance times may be dissociated from corresponding changes in.