The findings mainly surround changes to the main chamber of the heart - the left ventricle - which fills with blood and then pumps it out. As the heart ages, less blood enters the heart, and so less is pumped out.
The study builds on previous research that uses ultrasound to investigate how the heart changes with age. But this study, because it uses MRI scans, is able to make assessments using more detailed - and more reliable - images.
Left ventricle heart muscle grew in men, shrank slightly in women
Another distinguishing feature of the study is that it compares scans taken about a decade apart in the same patients. Most other studies of heart aging have tended to compare snapshots of young and old patients, which makes it difficult to rule out changes among individuals, such as lifestyle and health history.
John Eng, lead researcher and associate professor of radiological science at Johns Hopkins, notes:
"We had the opportunity to re-examine the same people after 10 years so that we could see what happened to their hearts after a decade. This is a more reliable way to assess left ventricular changes over time."
He and his colleagues found that in men, the heart muscle around the left ventricle grows and thickens with age, while in women it stays the same, or even shrinks slightly.
"Thicker heart muscle and smaller heart chamber volume both portend heightened risk of age-related heart failure," Prof. Eng explains, "but the gender variations we observed mean men and women may develop the disease for different reasons."
Heart filling capacity reduced with age, but more so in women
The participants in the study were aged between 54-94 and did not have any pre-existing heart disease when they enrolled. They underwent two sets of MRI scans, taken about 10 years apart between 2002-2012.
The MRI scans showed the interior and exterior of the heart in 3D, and allowed the researchers to assess size and volume of heart muscle, and from these to calculate its weight.
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