Exercise training in heart failure with preserved ejection fraction patients: the importance of resistance training

Abstract

Chronic heart failure with preserved ejection fraction (HFpEF) is the dominant form of HF, with an increasing prevalence and until recently very limited management options (e.g. diuretics, gliflozins, and incretin therapies). 1 Exercise intolerance (EI) presents one of the most common symptoms of HFpEF and is associated with a decreased quality of life (QoL) and increased risk of HF-related hospitalization and mortality. 1 The pathophysiology of EI is however complex and consists of pulmonary, skeletal muscle, vascular, and cardiac abnormalities that can substantially impact cardiac output, oxygen transport, and utilization to the exercising muscles, thereby leading to a substantial reduction in peak oxygen consumption (peak VO 2) and muscle strength. 1 This multiorgan dysfunction cannot be remediated by cardiovascular pharmacotherapy or cardiac implantable electronic devices only; therefore , optimal lifestyle management strategies are needed as well to improve the EI-related symptoms and outcomes. 1 Exercise training (ET), as part of cardiac rehabilitation (CR), may alleviate the symptoms of HFpEF and has been associated with superior improvements in (sub)maximal aerobic capacity, muscle strength, and QoL and decreases the risk of all-cause and HF hospitalization in HF patients. 2 Current evidence on ET in CR was established on mostly patients with HF with reduced EF (HFrEF), 2 while the evidence in HFpEF patients is growing. Recently completed studies have demonstrated superior effects of moderate-intensity continuous or high-intensity interval aerobic training (AT) alone or combined with resistance training (RT) on peak VO 2 over standard care alone. 3,4 While these studies have provided important information for improving exercise-based CR in HFpEF, there may be (emerging) ET approaches that should be adopted for this patient group. For example, recent evidence suggests that moderate-to-high load RT [MHL-RT; 55-80% of one repetition maximum (1-RM)] is safe and can provide greater benefits on peak VO 2 and maximal muscle strength, compared with AT alone in coronary artery disease (CAD) patients. 5 Therefore, it remains interesting to assess whether the implementation of MHL-RT may provide additional benefits on exercise performance in HFpEF patients. In this issue of the European Journal of Preventive Cardiology, Palau et al. 6 sought to determine the effects of novel ET approaches on improving symptoms of EI in HFpEF patients, all with chronotropic incompetence (chronotropic index <0.62 or <0.80 for patients previous on or without β-blocker therapy, respectively). The novelty of this paper is that the authors for the first time targeted the chronotropic incompetence with supervised ET intervention. In the study, the authors rando-mized 80 HFpEF patients to exercise counselling alone (counselling on regular unsupervised aerobic and resistance exercise), high-intensity AT alone (twice weekly, intervals of 1 min of high-intensity aerobic exercise separated by 2 min of active recovery), combination of inspiratory muscle training (20 repetitions at 40-60% of maximal inspiratory pressure performed twice daily), AT and low-load RT (LL-RT) (3 sets of 20 repetitions at 30-50% of 1-RM performed twice weekly), or MHL-RT (3 sets of 12 repetitions at 55-75% of 1-RM performed twice weekly). The study assessed changes in peak VO 2 (mL/kg/min and %), QoL, chronotropic response, and safety of and adherence to exercise intervention. After 12 weeks of intervention, all three supervised ET groups improved peak VO 2 max, health-related QoL, and chronotropic response to a greater extent when compared with exercise counselling alone. The combination of home-based inspiratory muscle training with supervised AT and MHL-RT was superior to AT alone on the improvement in peak VO 2 , while all supervised ET interventions induced similar improvements in QoL and chronotropic response, with 38% of the patients in the ET groups restoring their chronotropic response. In addition, all ET interventions were safe, well tolerated (all patients completed more than 83% of prescribed ET sessions) with no adverse cardiovascular events. This study elegantly presents several novel insights into the benefits of concurrent ET methods (e.g. combination of AT and RT) to tackle the highly prevalent EI symptoms of HFpEF patients. First, the study clearly shows that supervised ET should be offered for HFpEF patients instead of exercise counselling alone that showed no clinical benefits. Second, this study demonstrates the importance of combining AT