Therefore, exertional dyspnea in obese adults is not only an important and prolific clinical concern it is an obstacle to the prevention and treatment of obesity and obesity-related comorbidities. Although most obese adults with dyspnea on exertion are generally considered to be deconditioned, our preliminary data challenge this conventional wisdom. For example, in women with dyspnea on exertion, we have found the oxygen cost of breathing to be markedly increased and highly associated with exertional dyspnea. Thus, it is presently unclear if exertional dyspnea in obesity is due to cardiovascular deconditioning, in which exercise training would be dramatically beneficial, or to obesity-related changes in respiratory mechanics, in which aggressive weight loss measures may be necessary before exercise training can be tolerated.