Changes in aerobic capacity were evaluated after 12 weeks of training among a motivated heterogeneous group of cancer survivors (N = 54 [41 women and 13 men]), living at moderate altitude. Changes in power at lactate threshold (PT(lact)), peak power (P(peak)), and peak oxygen uptake (VO(2) peak) were evaluated in this group (average age, 53.8 + or - 10.8 years) that completed a minimum of 12 weeks of an individualized exercise program (on average 5 days x week(-1) for 47.5 + or - 17.2 min x session(-1)). Daily exercise duration was based on the goals and functional capacity of each individual. Training intensity for each subject was based on heart rate (HR) value at lactate threshold (T(lact)) obtained during a symptom-limited cardiopulmonary exercise test. Intensity was categorized into 5 ranges: recovery (60%-80% HR T(lact)); endurance (80%-100% HR T(lact)); threshold (100%-105% HR T(lact)); intervals (105%-115% HR T(lact)); and maximal efforts (> or = 115% HR T(lact)). Overall compliance with the exercise prescription was approximately 72% and subjects reported exercising within the 5 training ranges, 12.1%, 63.9%, 18.6%, 4.2%, and 1.2% of the time, respectively. After training, PT(lact) increased 9.5% (121.8 + or - 43.5 vs 133.2 + or - 34.1 W; P < 0.05), P(peak) increased 12.6% (175.5 + or - 55.6 vs 195.6 + or - 54.2 W; P < 0.05) and VO(2) peak increased 11.4% (33.4 + or - 12.5 vs 37.2 + or - 10.4 mL x kg(-1) x min(-1); P < 0.05). The results of this research indicate that: 1) cardiopulmonary exercise testing with lactate threshold determination was safe and effective in the evaluation and exercise prescription phase for a group of cancer survivors and 2) a training program based on 2 higher intensity workouts per week can elicit significant changes in aerobic capacity of a diverse group of cancer survivors.