Progressive Mechanical Ventilatory Constraints with Aging

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Abstract
To investigate the progressive nature of mechanical ventilatory constraints with aging, we studied 20 young (age 39 6 3 yr), 14 senior (70 6 2 yr), and 11 elderly (88 6 2 yr) men and women during exer- cise. All subjects had normal pulmonary function and performed graded cycle ergometry to exhaus- tion. Minute ventilation ( 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 3 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 E for a given submaximal work rate, although 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 V T ) increased with ag- ing; 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 con- straints during exercise. The impact of these constraints on exercise tolerance cannot be determined from this investigation and remains unclear. DeLorey DS, Babb TG. Progressive mechanical venti- latory constraints with aging. AM J RESPIR CRIT CARE MED 1999;160:169-177. . V