High intensity, interval exercise improves the Quality of Life and psychological status of patients with chronic heart failure: a phase III randomized clinical trial

Abstract

Background: The guidelines of the European Society of Cardiology recommend structured exercise training in heart failure; however, this has been poorly implemented in daily practise. The aim of this work was to evaluate the effect of high intensity, interval exercise on the quality of life (QoL) among chronic heart failure (CHF) patients. Methods: A phase III clinical trial. Of the 100 consecutive CHF patients (NYHA class II-IV, ejection fraction<30%) that were randomly allocated to exercise treatment (n=50) or control (n=50), 72 (exercise group, n=33, 63+9 years, 88% men, 70% ischemic CHF and exercise group, n=39, 56+11 years, 82% men, 70% ischemic CHF) completed the study. Particularly, the intervention group followed a high intensity, interval ergometric aerobic training (i.e., 30 sec at 100% of max workload, 30 sec at rest) for 30 min/day-by-12 weeks, whereas the control group received regular instructions. None of the participants in the intervention group complained about the training. OoL was evaluated through face-to-face interviews using the validated and translated Minnesota Living with Heart Failure questionnaire. Depressive symptomatology was evaluated using the validated and translated Zung Depression Scale. Oxygen uptake (VO2) at max and carbon dioxide production (VCO2) were also measured breath-by-breath, before and after intervention. The bioethics committee approved the protocol of the study; all participants signed an informed consent. Results: Both groups reported similar physical activity status at baseline, as assessed through the IPAQ (p=0.60), as well as had similar body mass index (p=0.08), smoking habits (p=0.17), history of hypertension (p=0.15), diabetes (p=0.46) and dyslipidemia (p=0.83). General mixed effects models revealed that intervention group reduced MLHFQ score by 373% (p<0.001) as compared with the control group (regular recommendations) in which no significant change was observed (p=0.09). Similarly, intervention group improved 6-minutes-walktest by 13% as compared with intervention group (p=0.10), the VO2 max level by 12.5% ml/kg/min (p=0.002), the VCO2 level by 21% L/min (p=0.01), and total power by 83% watts (p=0.04), as compared with the intervention group. Moreover, intervention group patients reduced significantly their depression score by 33% (p=0002) whereas no significant change in control group was observed (p=0.22). Conclusion: High intensity, systematic aerobic training, which was feasible to all CHF patients, should be strongly encouraged by clinicians, since it improves their QoL, by increasing their fitness level and their psychological status.