The Obesity Paradox in Cardiovascular Diseases

Obesity is associated with several cardiac structural, functional, hemodynamic, and neurohormonal changes, resulting in increased risk for cardiovascular diseases (CVDs). Particularly, obesity is associated with greater risk for heart failure, hypertension, coronary heart disease, atrial fibrillation, and more recently, pulmonary arterial hypertension. Once such diseases have been diagnosed, however, patients with obesity present a more favorable prognosis compared to leaner patients. Such a phenomenon has been defined as “the obesity paradox.” The mechanisms leading to improved outcomes in obese patients are still largely unknown; however, most of the studies investigating the role of obesity on the development and progression of CVD were limited by the use of the body mass index, which does not distinguish between different body composition (BC) compartments, which have distinctive effects on the CV system. In this review, we will discuss the increased risk of CVD in patients with obesity and the mechanisms through which obesity and particularly BC compartments (e.g., skeletal muscle mass) may confer protection once CVDs have been diagnosed. We will then review the impact of cardiorespiratory fitness in modulating the effects of obesity in patients with CVD and the role of unintentional and intentional weight loss in such conditions. Finally, we will discuss the potential beneficial effects of therapeutics targeting BC compartments in determining prognosis in patients with established CVD.