The Effect of Exercise Training Intensity on Quality of Life in Heart Failure Patients: A Systematic Review and Meta-Analysis

OBJECTIVES: To establish if exercise training intensity produces different effect sizes for quality of life in heart failure. BACKGROUND: Exercise intensity is the primary stimulus for physical and mental adaptation. METHODS: We conducted a MEDLINE search (1985 to February 2016) for exercise-based rehabilitation trials in heart failure using the search terms 'exercise training', 'left ventricular dysfunction', 'peak VO2', 'cardiomyopathy', and 'systolic heart dysfunction'. RESULTS: Twenty-five studies were included; 4 (16%) comprised high-, 10 (40%) vigorous-, 9 (36%) moderate- and 0 (0%) low-intensity groups; two studies were unclassified. The 25 studies provided a total of 2,385 participants, 1,223 exercising and 1,162 controls (36,056 patient-hours of training). Analyses reported significant improvement in total Minnesota living with heart failure (MLWHF) total score mean difference (MD) -8.24, 95% CI -11.55 to -4.92, p < 0.00001. Physical MLWHF scorewas significantly improved in all studies (MD -2.89, 95% CI -4.27 to -1.50, p < 0.00001). MLWHF total score was significantly reduced after high- (MD -13.74, 95% CI -21.34 to -6.14, p = 0.0004) and vigorous-intensity training (MD -8.56, 95% CI -12.77 to -4.35, p < 0.0001) but not moderate-intensity training. A significant improvement in the total MLWHF score was seen after aerobic training (MD -3.87, 95% CI -6.97 to -0.78, p = 0.01), and combined aerobic and resistance training (MD -9.82, 95% CI -15.71 to -3.92, p = 0.001), but not resistance training. CONCLUSIONS: As exercise training intensity rises, so may the magnitude of improvement in quality of life in exercising patients. Aerobic-only or combined aerobic and resistance training may offer the greatest improvements in quality of life.