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 exhau stion. Minute ventilation ((V) over dot E), lung volume, and expiratory air flow limitation (EAFL) were measured during each 1-min increment in work ra te. Data were analyzed by two-way analysis of variance (ANOVA; age x gender ) at rest, ventilatory threshold (VTh), and peak exercise. If an interactio n was present, each gender was analyzed with a one-way ANOVA. Aging resulte d in an increased (V) over dot E for a given submaximal work rate, although (V) over dot E during peak exercise was lowest in the elderly group (p < 0 .01). End-expiratory lung volume (EELV, % of TLC) in men increased progress ively with age and all groups were different at VTh (p < 0.01) and peak exe rcise (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 e xercise (p < 0.01) than the young group. Additionally, the normal decrease in EELV during the early stages of exercise was not observed in elderly sub jects. End-inspiratory lung volume (EILV) also progressively increased with aging; senior and elderly subjects had a higher EILV at rest (p < 0.05), V Th (p < 0.01), and peak exercise (p < 0.01) than young subjects. EAFL (% of VT) increased with aging; elderly subjects experienced greater EAFL at res t (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 ar e 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 remain s unclear.