BACKGROUND: Exercise training improves functional capacity in patients with systolic dysfunction (SD), but the role of exercise training in diastolic dysfunction (DD) is unclear. We compared the responses of patients with exercise intolerance and SD or DD to 16 weeks of exercise training. METHODS: Fifty-one patients with SD and DD were enrolled in exercise training, which was completed in 24 patients with SD (22 men, 62 +/- 8 years old, ejection fraction <35%) and 18 patients with DD (9 men, 65 +/- 5 years old, ejection fraction >45%). Peak VO2, quality of life (Minnesota Living with Heart Failure and Hare-Davis questionnaires), and echocardiographic measures (ejection fraction, systolic and diastolic tissue velocity, and filling pressure) were performed at baseline and after 16 weeks of training. RESULTS: Patients with SD and those with DD showed similar baseline peak VO2 (11.9 +/- 2.5 vs 12.5 +/- 4.1 mL/[kg min], P = .55) and E/E' ratio (21 +/- 13 vs 14.4 +/- 15, P = .07), but different systolic velocity (3.4 +/- 1.0 vs 5.5 +/- 1.7 cm/s, P < .001), diastolic velocity (3.9 +/- 1.5 vs 5.1 +/- 1.8 cm/s, P = .05), and ejection fraction (26 +/- 8% vs 55 +/- 9%, P < .001). Baseline quality of life scores were worse in patients with SD. There was a similar increment in peak VO2 in SD (24%, P = .001) and DD (30%, P < .001) after exercise training, but this did not correlate with improved diastolic parameters. Quality of life scores improved in both SD and DD, although SD scores remained significantly worse. CONCLUSIONS: In patients with exercise limitation attributed to DD, the improvement in peak VO2 and quality of life with exercise training is similar to those with SD, but unrelated to changes in diastolic function.