A review regarding the article 'Supervised exercise training in heart failure with preserved ejection fraction: A systematic review and meta-analysis of randomized controlled trials.'.

Heart failure is a clinical syndrome with different etiologies and phenotypes. For all forms, supervised exercise training and individual physical activity are class IA recommendations in current guidelines. Over the past two decades it has become recognized that physical deconditioning may play a key role in the progression of symptoms and poor outcomes. A number of prior studies have assessed the ability of exercise training to improve functional capacity in patients with HF. Most of these previous studies showed positive effects of exercise training on exercise capacity, quality of life, and biomarkers and observed relatively few complications during training. These studies also suggested that exercise training might improve survival and decrease HF hospitalizations. Despite the failure of pharmacological interventions to reduce mortality and hospitalization in HFpEF, exercise training has shown efficacy in improving maximal exercise capacity, assessed through peak oxygen consumption (peak V˙o2), in clinically stable patients. Nonetheless, there remains a safety concern regarding exercise training in HF. Although the complication rate for patients participating in cardiac rehabilitation has been reported to be extremely low, the complication rate for HF patients in clinical trials of exercise training has been substantially higher. One potential reason is the 100-fold increased risk for myocardial infarction and 50-fold increased risk of sudden death that exercisers, who are habitually sedentary, experience when initiating exercise training. Additionally, comprehensive insights into the potential effects of exercise training, not only on critical clinical outcomes such as hospitalization, mortality, and cardiovascular events but also on cost-effectiveness, require longer-term trials.