Even the hearts of men and women age differently, a finding that could have implications in treating heart disease. So report Johns Hopkins University researchers in the journal Radiology after they combed through the results of a longitudinal study following nearly 3,000 men and women for, on average, nearly a decade. It turns out that the heart muscle around the left ventricle—which pumps blood throughout the body—grew larger and thicker over time in men, while in women it tended to stay the same or get smaller. Over time, its volume also decreased more in women than in men, which they call a "fascinating discrepancy." Says a senior researcher: "Our results are a striking demonstration of the concept that heart disease may have different pathophysiology in men and women, and of the need for tailored treatments that address such important biologic differences."
It's the first long-term study that uses MRI scans to observe the structure and function of the left ventricle, and because women are so rarely included in heart research, it's the first to observe these differences, notes Live Science. (Just last year, the National Institutes of Health announced a policy shift requiring that any studies it funds use both male and female cells, which is in addition to earlier requirements that women be included in clinical trials, reports Vice.) Another researcher says their findings pose a host of new questions: "Treatments related to the shape changes may have to be different—like treatment for heart failure might have to be different for men and women. It's the first time we've made this observation, so it's going to require more research to try to understand what the cause of that is." (Any idea how old your heart is?)