Abstract Background: Higher body mass index (BMI) has been associated with improved outcomes in heart failure with reduced ejection fraction. This finding has led to the concept of the obesity paradox. Objective: To investigate the impact of exercise tolerance and cardiorespiratory capacity on the obesity paradox. Methods: Outpatients with symptomatic heart failure and left ventricular ejection fraction (LVEF) ≤ 40%, followed up in our center, prospectively underwent baseline comprehensive evaluation including clinical, laboratorial, electrocardiographic, echocardiographic, and cardiopulmonary exercise testing parameters. […]