Cardiorespiratory responses to a 12wk moderate exercise training program were examined in 30 sedentary elderly women (mean age = 73.6 +/- 0.7 yr). In addition, 12 highly conditioned (HC) older women (mean age = 72.5 +/- 1.8 yr; 11.2 +/- 1.2 yr training; 1.6 +/- 0.2 hr.d-1 aerobic activity) were tested at baseline for cross-sectional comparisons. The VO2max and VEmax of the HC subjects were 67% and 36% higher, respectively, (p < 0.001) than the combined sedentary subjects at baseline. Sedentary subjects were randomly assigned to a walking (WALK) or calisthenics control (CAL) group. The WALK group exercised 5 d.wk-1 for 30-40 min per session at 60.0 +/- 1.9% heart rate reserve while the CAL group engaged in mild musculoskeletal exercise. The WALK group demonstrated significant improvement in VO2max compared to CAL subjects at 12 wk (12.6% vs 2.2%, F = 5.74, p = 0.005). These data show that septuagenarian women demonstrate significant improvement in maximal cardiorespiratory fitness through moderate exercise training.