Sex hormones have a major impact on nerve, blood vessel and cardiac control. The secretion of estrogen, and perhaps progesterone, has a protective effect, which is why women are less likely to develop cardiovascular disease until menopause. However, the cardiovascular system has mainly been studied in male populations, creating a disparity that trickles down to the prevention and treatment of cardiovascular disease in women. Charlotte Usselman, professor in the Department of Kinesiology and Physical Education at McGill University, has made it her mission to bridge the knowledge gap.
To lead the project, her team is relying on leading-edge techniques such as microneurography, which measures the activity of the sympathetic nervous system by inserting electrodes the size of a human hair into the nerves. The project participants are healthy women, including women with polycystic ovary syndrome (PCOS) who produce a significant amount of androgens and testosterone in particular. The subjects are assessed at rest and during acute cardiovascular disturbances, for instance when they’re asked to immerse their hand in ice water.
These clinical studies enable comparisons between the neurological and cardiovascular functions of women and men and shed light on the protective effect of female sex hormones on heart health. They also help explain why women with PCOS, which affects some 10% of women of childbearing age, are at a greater risk of cardiovascular disease. In the longer term, the research could lead to health recommendations that are better adapted to the physiologies of certain populations, such as women in menopause.