MAXIMAL AEROBIC CAPACITY AND TOTAL BLOOD-VOLUME IN HIGHLY TRAINED MIDDLE-AGED AND OLDER FEMALE ENDURANCE ATHLETES

The primary aim of this study was to test the hypothesis that, relativ e to age-matched sedentary controls, middle-aged and older female endu rance athletes exhibit levels of maximal rate of O-2 consumption (Vo(2 max)) similar to those previously reported in male endurance athletes in the same age group and, furthermore, that these high levels of Vo(2 max) are associated with elevated total blood volumes. To accomplish t his, we measured V-o2max and total blood volume in 13 highly trained f emale runners and 17 healthy untrained women 50-70 yr of age. The runn ers had lower (P < 0.001) body mass index and estimated body fat relat ive to the controls. They also had higher levels of Vo(2max) (2.70 +/- 0.08 vs. 1.74 +/- 0.06 l/min, 48.6 +/- 1.9 vs. 26.5 +/-0.8 ml.kg(-1). min(-1), 58.0 +/- 1.8 vs. 38.8 +/- 1.2 ml.kg fat-free mass(-1).min(-1) ; all P < 0.001) and total blood volume (4,964 +/- 226 vs. 4,336 +/- 1 30 ml, P < 0.02; 89 +/- 4 vs. 64 +/- 2 ml/kg, P < 0.001; 106 +/- 4 vs. 96 +/- 3 ml/kg fat-free mass, P < 0.05). The elevated total blood vol umes in the runners were due to both higher plasma and erythrocyte vol umes. In addition, hematocrit and hemoglobin concentrations were highe r in the runners (P < 0.007). Vo(2max) was strongly (P < 0.001) relate d to total blood volume (r = 0.79), plasma volume (r = 0.76), and eryt hrocyte volume (r = 0.78) when all were expressed relative to body wei ght. These findings support the hypothesis that highly trained 50- to 70-yr-old female endurance athletes are capable of exhibiting levels o f Vo(2max) similar to 85% higher on average than age-matched healthy u ntrained controls, consistent with previous findings in trained and un trained men of this age. Furthermore, the high levels of Vo(2max) in t he athletes are associated with elevated total blood volumes.