Updates on obesity and the obesity paradox in cardiovascular diseases.

The prevalence of obesity has reached pandemic proportions worldwide and certainly in the United States. Obesity is a well-established independent risk factor for development of many cardiovascular diseases (CVD), including heart failure, coronary heart disease, atrial fibrillation, and hypertension. Therefore, it is logical to expect obesity would have a strong correlation with CVD mortality. However, a substantial body of literature demonstrates a paradox with improved prognosis of overweight and obese patients with established CVD compared to lean patients with the identical CVD. Surprisingly, similar data has also shown that cardiovascular fitness, rather than weight loss alone, influences the relationship between obesity and mortality in those with established CVD. The impact of fitness, exercise, physical activity (PA), and weight loss and their relationship to the obesity paradox are all reviewed here.