Heart failure with reduced ejection fraction (HFrEF) is frequently associated with abnormalities in body composition, including reduced skeletal muscle mass and sarcopenia, which are independent predictors of reduced exercise tolerance, impaired quality of life, and increased mortality. Despite advances in pharmacological therapy, evidence-based non-pharmacological strategies aimed at preventing muscle mass loss remain limited.

This randomized controlled trial aims to evaluate the effects of dietary intervention based on the DASH diet with high-protein elements, resistance exercise training, and their combination on skeletal muscle mass, functional capacity, echocardiographic parameters, biochemical markers, and quality of life in patients with HFrEF.

Inclusion Criteria:

Written informed consent obtained prior to participation Age >30 years Diagnosis of chronic heart failure, NYHA functional class I-III Left ventricular ejection fraction <40%

Exclusion Criteria:

NYHA functional class IV heart failure Potentially reversible cause of heart failure Estimated glomerular filtration rate <30 mL/min Severe anemia (hemoglobin <9 g/dL) Uncontrolled thyroid disease Severe hepatic dysfunction History of hyperkalemia or hyperkalemia at baseline Epilepsy Presence of joint endoprostheses Gastrointestinal disorders limiting adherence to the DASH diet Physical limitations precluding participation in structured exercis