BACKGROUND: The effect that supervised or unsupervised exercise training has on aerobic capacity (peak oxygen consumption [VO2peak]), muscle strength and quality of life in older women with heart failure remains unknown. OBJECTIVE: To examine the effect of six months (three months supervised followed by three months unsupervised) of aerobic training (AT) or combined aerobic and strength training (CAST) on VO2peak, muscle strength and quality of life in older women with heart failure. METHODS: Twenty older women (mean age +/- SD, 72+/-8 years) with clinically stable heart failure were randomly assigned to AT (n=10) or CAST (n=10). Supervised AT was performed two days per week at 60% to 70% heart rate reserve, whereas unsupervised training was performed two days per week at a rate of perceived exertion of 12 to 14 on the Borg scale. The CAST group also performed one to two sets of low-to-moderate intensity strength training two days per week. RESULTS: Supervised AT or CAST resulted in an increase in VO2peak (12%; P<0.05) and leg press strength (13%; P<0.05) that returned to baseline after unsupervised training. Vertical row strength was greater (+23%; P<0.05) after supervised CAST and remained unchanged after supervised or unsupervised AT. Supervised or unsupervised exercise training was not associated with a significant change in quality of life. CONCLUSIONS: Supervised AT or CAST are effective modes of exercise to improve VO2peak and muscle strength in older women with heart failure. However, the improvements in VO2peak and muscle strength are not maintained with unsupervised exercise training.