Emerging research into why some women have hot flashes while others with identical hormonal profiles do not has shed light on a possible connection between hot flashes and heart disease. A key preliminary study (published in 2008) of 492 women ages 45 to 58 (who participated in The Study of Women's Health Across the Nation Heart Study) found women with hot flashes had greater aortic calcification or plaque (a build up of calcium deposits in the body's biggest artery and an early sign of heart disease) than women who did not have hot flashes. In a follow-up to the study published this past December by the same group at the University of Pittsburgh, the longer a woman reported having hot flashes, the more likely she was to have calcifications.
Blood vessels typically dilate (expand) during a hot flash. A growing body of evidence suggests hot flashes are associated with adverse vascular changes. But these studies on aortic calcification are among the first to suggest a link between the vascular changes associated with hot flashes and subclinical (undiagnosed) cardiovascular disease. The Pittsburgh docs also published a third study this past December that provides an additional connection between hot flashes and heart health.
The third study raised the possibility that demands on the heart increase during a hot flash. During a hot flash the body experiences an increase in heart rate and a decrease in vagal control of the heart (measured by how quickly the heart rate returns to its resting rate after elevation, a statistic known as Heart Rate Variability). Vagal control is the mechanism by which the heart receives the message to relax or slow down in the form of a chemical messenger (the neurotransmiter acetylcholinehe) traveling via the vagus nerve, the body's largest and longest nerve. The vagus nerve helps maintain a balance between the sympathetic, adrenaline-driven, half of the nervous system and its calming, parasympathetic other half. This decrease in vagal control during a hot flash is a sign of stress on the system.
If this is all sounding a little scary, and giving you a hot flash just thinking about it, keep in mind this is preliminary research. It's been estimated that 75%-80% of women experience hot flashes at some point from the time estrogen begins to recede in the menopausal phases of life and for some women until many years after their last menstrual period. This intriguing research is not enough evidence to confirm that hot flashes are predictive of heart disease. But it is an important area for further investigation given that heart attacks remain the leading cause of death for women in the U.S., with the incidence dramatically increasing after menopause.
Bottom line: it is important for everyone to check their heart health at middle age. This latest research just confirms that. In my next blog, I will give you my take on what constitutes a thorough cardiovascular evaluation.