Over the last several decades, female athletes have often been left out of sports science research, and the majority of studies have focused primarily on young, healthy males as subjects. It has only been in recent years that researchers have begun to include women in their studies, and, perhaps not surprisingly, some differences are beginning to emerge. A recent study looking at the differences between male and female marathoners found that women’s hearts actually respond differently than men’s after training for a marathon.
The paper, entitled “Sex differences in cardiovascular adaptations in recreational marathon runners,” aimed to examine various changes in heart function in male and female marathoners and recreational athletes. The researchers included 52 marathoners (28 females and 24 males) who had completed five to seven marathons over three years and 49 recreationally active adults (25 females and 24 males) as controls.
The researchers studied the hearts of each participant, focusing on three main measurements:
- Left ventricle function: the left ventricle pumps oxygen-rich blood to the rest of the body.
- Aortic stiffness: occurs when the elastic fibers within the arterial wall (elastin) begin to fray due to mechanical stress.
- Ventricular-vascular coupling: the ratio of arterial to left ventricle elastance, a key determinant of cardiac performance.
After studying the hearts of all the participants, the researchers found that women who have completed multiple marathons do not have reduced left ventricle function or aortic stiffness compared to male marathoners or female recreationally active athletes (both of which are good things). Interestingly, they appear to have better ventricular-vascular coupling compared to the other test groups, which means their hearts are more mechanically efficient after undergoing a marathon training cycle. In other words, women’s hearts may respond better to marathon training than men’s.
The reason for this is unclear, but the researchers believe it could have something to do with the estrogen levels in female athletes. Studies show that estrogen positively modulates cardiac hypertrophy (the heart’s tendency to get bigger with training), lowers blood pressure and decreases arterial stiffness, all of which make for a healthier, stronger heart.
The researchers conclude the studying by acknowledging that future studies are needed to better understand the influence of sex hormones (in particular, estrogen) on cardiovascular adaptations in marathon runners. This will create a greater understanding of how women adapt to marathon training and may lead to better training protocols for female distance runners in the future.