GREATER RATE OF DECLINE IN MAXIMAL AEROBIC CAPACITY WITH AGE IN PHYSICALLY ACTIVE VS. SEDENTARY HEALTHY WOMEN

Using a meta-analytic approach, we recently reported that the rate of decline in maximal oxygen uptake ((V) over dot o(2max)) With age in he althy women is greatest in the most physically active and smallest in the least active when expressed in milliliters per kilogram per minute per decade. We tested this hypothesis prospectively under well-contro lled laboratory conditions by studying 156 healthy, nonobese women (ag e 20-75 yr): 84 endurance-trained runners (ET) and 72 sedentary subjec ts (S). ET were matched across the age range for age-adjusted IO-km ru nning performance. Body mass was positively related with age in S but not in ET. Fat-free mass was not different with age in ET or S. Maxima l respiratory exchange ratio and rating of perceived exertion were sim ilar across age in ET and S, suggesting equivalent voluntary maximal e fforts. There was a significant but modest decline in running mileage, frequency, and speed with advancing age in ET. (V) over dot O-2max (m l.kg(-1).min(-1)) was inversely related to age (P < 0.001) in ET (r = -0.82) and S (r = -0.71) and was higher at any age in ET. Consistent w ith our meta-analysic findings, the absolute rate of decline in (V) O- 2max was greater in ET (-5.7 ml.kg(-1).min(-1).decade(-1)) compared wi th S (-3.2 ml.kg(-1).min(-1).decade(-1); P < 0.01), but the relative ( %) rate of decline was similar (-9.7 vs -9.1%/decade; not significant) . The greater absolute rate of decline in (V) over dot O-2max in ET co mpared with S was not associated with a greater rate of decline in max imal heart rate (-5.6 vs. -6.2 beats.min(-1).decade(-1)), nor was it r elated to training factors. The present cross-sectional findings provi de additional evidence that the absolute, but not the relative, rate o f decline in maximal aerobic capacity with age may be greater in highl y physically active women compared with their sedentary healthy peers. This difference does not appear to be related to age-associated chang es in maximal heart rate, body composition, or training factors.