Having a Smaller Heart Can Reduce Respiratory Function in Middle-Aged Women

By Tamara Thomas - Last Updated: March 11, 2023

Middle-aged women with smaller hearts are more likely to have lowered cardiorespiratory function (CRF). This condition can lead to disability, heart failure, and premature death, according to a new study published in JACC: Cardiovascular Imaging.

The study, led by Associate Professor Andre La Gerche, sought to determine if a connection and relation existed between CRF and the size and function of heart ventricles.

Studies in athletes over many years found that having a bigger heart is connected to increased CRF. However, La Gerche and his team demonstrated that the opposite is true—having a smaller heart is linked to lower CRF. They also identified a comprehensive physiological mechanism to explain this relationship.

For the study, 185 healthy women over 30 (average age: 51) underwent a medical test to check their CRF. The researchers then examined how the women’s CRF, heart size, and heart functions were related using a scientific calculation to identify and predict future outcomes.

Researchers also observed how different heart sizes affect the heart’s function during exercise by dividing the women into 4 groups based on their heart size at rest.

“We made two important and novel findings,” La Gerche stated. “The first is that there is a strong positive relationship between ventricular size and CRF, and secondly, that there is diminished augmentation of cardiac function during exercise in those women with small cardiac size.”

He added that a possible explanation for the low CRF observed in women with a small heart size is a “double hit” effect. A smaller heart has both a reduced resting capacity and a reduced ability to increase pumping capacity during exercise.

“In younger people, fitness is tested when having fun with friends. In middle-aged and older individuals, fitness defines your resilience to illness, operations, and health challenges. You need to build your heart muscle when you are young to have the reserve to cope with challenges when older. Our hospitals are disproportionately weighted by people in whom modest illnesses push their hearts to their capacity. This is, at least in part, preventable,” Andre La Gerche said.

La Gerche points out that despite the limitations imposed by having a small heart, we can expand the size of our hearts, stating, “Although we found in this study that women with the smallest ventricles had lower exercise capacity and a constrained ability to increase capacity, we do know that through exercise, we can all change the size of our hearts.”

Source: Medical Xpress

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