Gender Affects Heart's Response to Obesity

Female gender and obesity predict greater myocardial blood flow and oxygen consumption

TUESDAY, July 22 (HealthDay News) -- Myocardial metabolic responses to obesity significantly vary by gender, according to the results of a study published in the July issue of the Journal of the American College of Cardiology: Cardiovascular Imaging.

Linda R. Peterson, M.D., of the Washington University School of Medicine in St. Louis, and colleagues used echocardiography and positron emission tomography to assess 86 men and women, including 35 who were obese.

In women, the researchers found that obesity amplified a pre-existing increase in myocardial blood flow and oxygen consumption. In women -- but not in men -- they found a direct relationship between body mass index, myocardial blood flow and oxygen consumption. They also found that the women's hearts were less efficient despite the increased cardiac work.

"Because energy can neither be created nor destroyed, the results suggest impaired coupling of fatty acid oxidation to adenosine triphosphate production or futile cycling of substrates in the heart of obese women," state the authors of an accompanying editorial. "The investigators imply that uncoupling proteins are the mediators for reduced cardiac efficiency. This is a reasonable speculation; although, there is also a cardioprotective role for uncoupling proteins that needs to be considered."

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