The obesity paradox in heart failure: What is the role of cardiorespiratory fitness?

The obesity paradox describes a survival benefit for higher body mass index in patients with heart failure. But other factors like cardiorespiratory fitness may play a role in heart failure development, severity, and survival. Although more research is needed to better understand the relationships between body mass index and fitness in patients with heart failure, evidence indicates that recommending weight loss and an exercise program is appropriate for most patients. KEY POINTS Obesity increases the risk of developing heart failure regardless of fitness level, but better fitness attenuates the risk. Weight appears to be only part of the obesity paradox story. Evidence indicates that cardiorespiratory fitness is a major factor influencing the paradox. Fitness modifies the obesity paradox in patients with heart failure and reduced ejection fraction, with the paradox remaining strongest in patients who are less fit. Although more research is needed on risk reduction for heart failure, evidence indicates that intentional weight loss and increased fitness are advisable for select patients.