![Men's and women's hearts don't grow old the same way. Men's and women's hearts don't grow old the same way.](/images/transform/v1/crop/frm/silverstone-feed-data/4a5192f6-8ad8-4ce9-8c14-e2faa708d967.jpg/r0_0_1024_717_w1200_h678_fmax.jpg)
Male and female hearts age differently according to new research.
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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. But in men the heart muscle that encircles the chamber grows bigger and thicker with age, while in women, it get retains its size or gets somewhat smaller.
The research by the John Hopkins University School of Medicine involved the analysis of MRI scans of the aging hearts of nearly 3,000 adults ages 54 to 94, without preexisting heart disease.
Participants were followed between 2002 and 2012, at six hospitals across the United States where each one of them underwent MRI testing at the beginning of the study and once more after a decade.
The scientists says that while the results do not explain exactly what causes the sex-based differences, they may shed light on different forms of heart failure seen in men and women that may require the development of gender-specific treatments.
“Thicker heart muscle and smaller heart chamber volume both portend heightened risk of age-related heart failure but the gender variations we observed mean men and women may develop the disease for different reasons,” says lead investigator John Eng, M.D., associate professor of radiological science.
The research team cautions that its study was not designed to find what exactly fuels the differences in cardiac physiology between the sexes but says this “fascinating discrepancy” demands further investigation to figure it out.
The MRI scans provided researchers with 3-D images of the heart’s interior and exterior, allowing them to determine the size and volume of the heart muscle. Adding these to the already known density of the muscle, they were able to calculate its weight.
Over a period of 10 years, the weight of the heart’s main pumping chamber — the left ventricle — increased by an average of 8 grams in men and decreased by 1.6 grams in women. The heart’s filling capacity — marked by the amount of blood the left ventricle can holds between heartbeats — declined in both sexes but more precipitously so in women, by about 13 milliliters, compared with just under 10 milliliters in men.
The differences in size, volume and pumping ability occurred independently of other risk factors known to affect heart muscle size and performance, including body weight, blood pressure, cholesterol levels, exercise levels and smoking.