Here is one more way men and women are different: research published online Oct. 20, 2015 in Radiology found that male and female hearts do not age the same way.
For the study, researchers reviewed MRI heart scans performed on almost 3,000 older adults, ages 54 to 94, without existing heart disease. (Scans were given 10 years apart.) The scans showed that in both sexes, the main heart chamber—the left ventricle, which fills with and then forces out blood—gets smaller with time. As a result, less blood enters the heart, and less gets pumped out to the rest of the body.
However, in men, the heart muscle that encircles the chamber grows larger and thicker with age. (In women, it either retains its size or gets somewhat smaller.) The combination of a thicker heart muscle and smaller heart chamber volume heightens the risk of heart failure in men, says lead researcher Dr. John Eng of the Johns Hopkins University School of Medicine.
The researchers are not sure what causes the sex-based variation, but the results may change how doctors treat heart disease in the future. "Treatment now does not differ by sex, even though it appears the mechanism of heart disease is not the same between men and women," says Dr. Eng. "Our study implies that optimum treatment for men may be different."