Progressive mechanical ventilatory constraints with aging.

To investigate the progressive nature of mechanical ventilatory constraints with aging, we studied 20 young (age 39 +/- 3 yr), 14 senior (70 +/- 2 yr), and 11 elderly (88 +/- 2 yr) men and women during exercise. All subjects had normal pulmonary function and performed graded cycle ergometry to exhaustion. Minute ventilation (V E), lung volume, and expiratory airflow limitation (EAFL) were measured during each 1-min increment in work rate. Data were analyzed by two-way analysis of variance (ANOVA; age x gender) at rest, ventilatory threshold (VTh), and peak exercise. If an interaction was present, each gender was analyzed with a one-way ANOVA. Aging resulted in an increased V E for a given submaximal work rate, although V E during peak exercise was lowest in the elderly group (p < 0.01). End-expiratory lung volume (EELV, % of TLC) in men increased progressively with age and all groups were different at VTh (p < 0.01) and peak exercise (p < 0.01). In women, EELV (% of TLC) also increased with aging, the senior and elderly subjects had a greater EELV at VTh (p < 0.01) and peak exercise (p < 0.01) than the young group. Additionally, the normal decrease in EELV during the early stages of exercise was not observed in elderly subjects. End-inspiratory lung volume (EILV) also progressively increased with aging; senior and elderly subjects had a higher EILV at rest (p < 0.05), VTh (p < 0.01), and peak exercise (p < 0.01) than young subjects. EAFL (% of VT) increased with aging; elderly subjects experienced greater EAFL at rest (p < 0.05), VTh (p < 0.01), and peak exercise (p < 0.01) than both young and senior subjects. We conclude that mechanical ventilatory constraints are progressive with aging, elderly subjects demonstrating marked mechanical ventilatory constraints during exercise. The impact of these constraints on exercise tolerance cannot be determined from this investigation and remains unclear.