LONGITUDINAL EFFECTS OF AGING ON LUNG-FUNCTION AT REST AND EXERCISE IN HEALTHY ACTIVE FIT ELDERLY ADULTS

We retested 18 healthy, active, and highly fit [maximal O-2 consumptio n (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 capac ity did not change; vital capacity, forced expiratory volume in 1 s, a nd maximal volitional flow rates decreased; and residual volume and cl osing capacity/TLC increased 11-13%, all of which were greater than pr edicted from cross-sectional data. At maximum exercise over the 6-yr p eriod, VO2max fell 11.2 +/- 3.4% (45.0-->40.3 ml . kg(-1) . min(-1)), six (of 18) subjects showed significant arterial hypoxemia (arterial O -2 saturation less than or equal to 92%), and maximum heart rate and m inute ventilation-to-O-2 consumption ratio (VE/VO2) were unchanged. At any given submaximal work rate, VE and breathing frequency were highe r, the degree of expiratory flow limitation increased, and end-expirat ory and end-inspiratory lung volumes were unchanged but remained signi ficantly 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 t he increased levels of ventilatory work during exercise that occur wit h healthy aging over the sixth and seventh decades of life.