Longitudinal effects of aging on lung function at rest and exercise in healthy active fit elderly adults

Abstract

We retested 18 healthy, active, and highly fit [maximal O2 consumption (VO2max) 201 +/- 12% of predicted] older adults over a 6-yr period (mean age 67-->73 yr) to determine the longitudinal effects of aging on lung function at rest and during exercise. In the 6-yr period, total lung capacity (TLC), functional residual capacity, and diffusion capacity did not change; vital capacity, forced expiratory volume in 1 s, and maximal volitional flow rates decreased; and residual volume and closing capacity/TLC increased 11-13%, all of which were greater than predicted from cross-sectional data. At maximum exercise over the 6-yr period, VO2max fell 11.2 +/- 3.4% (45.0-->40.3 ml.kg-1.min-1), six (of 18) subjects showed significant arterial hypoxemia (arterial O2 saturation < or = 92%), and maximum heart rate and minute ventilation-to-O2 consumption ratio (VF/VO2) were unchanged. At any given submaximal work rate, VE and breathing frequency were higher, the degree of expiratory flow limitation increased, and end-expiratory and end-inspiratory lung volumes were unchanged but remained significantly higher relative to young adults. We conclude that in contrast to implications from cross-sectional data, our longitudinal findings demonstrate that habitual physical activity and high aerobic capacity modify neither the normal deterioration in resting lung function nor the increased levels of ventilatory work during exercise that occur with healthy aging over the sixth and seventh decades of life.