Effect of high- versus low-frequency exercise training in multidisciplinary cardiac rehabilitation on health-related quality of life.

BACKGROUND The authors examined the importance of the frequency of aerobic exercise training in multidisciplinary rehabilitation in improving health-related quality of life in the short run in patients with documented coronary artery disease. METHODS Patients (114 males and 16 females; age range, 32-70 years) were randomized into either a high-frequency or a low-frequency exercise training program (10 versus 2 sessions per week, respectively) as part of a 6-week multidisciplinary cardiac rehabilitation program. The General Health Questionnaire and the RAND-36 were used to assess changes in psychological distress and subjective health status. RESULTS After 6 weeks, high-frequency patients reported significantly more positive, change in "psychological distress" (P < 0.05), "mental health" (P = 0.05), and "health change" (P < 0.01), than low-frequency patients. Apart from changes in mean scores, individual effect sizes indicated that a significantly greater percentage of high-frequency patients experienced substantial improvements in "psychological distress" (P < 0.01), "physical functioning" (P < 0.05), and "health change" (P < 0.05), compared with low-frequency patients. In addition, deterioration of quality of life was observed in a considerable number of high-frequency patients (ranging from 1.7% to 25.8% on the various measures). CONCLUSIONS The frequency of aerobic exercise has a positive, independent effect on psychological outcomes after cardiac rehabilitation. However, this benefit after high-frequency rehabilitation appears to be limited to a subgroup of patients. Further investigation is required to identify these patients. Results provide input into recent controversies regarding the role of exercise training in cardiac rehabilitation.