Respiratory limitations in the aging population.

In the normal aging population, there is no evidence that ventilation limits exercise. At all ages, normal persons have adequate ventilation during exercise to avoid arterial hypoxemia. Despite adequate oxygenation, however, indirect evidence suggests that with normal aging the loss of elastic recoil and reductions in maximal expiratory flow may impose indirect ventilatory limitations. Exercise capacity may be decreased by these constraints or by resultant respiratory muscle fatigue. This article explores the indirect evidence for ventilatory limitation during aging.