Those of us in the Biomedical Sciences Master’s Program recently read a paper by Dr. Campisi on the disadvantages women experience when exercising in their luteal phase of their menstrual cycle. This got me thinking about how many athletes, especially elite runners, don’t have their menses due to the intense training plan and what impact that suppression could have on their health.
As everyone knows puberty for young females is marked by their first menses (period), which for most people will continue to occur monthly unless otherwise prompted. In normal puberty, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus in a pulsatile fashion, and stimulates both the synthesis and secretion of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the anterior pituitary (Golden and Carlson, 2008). FSH and LH are important because when they are released they promote ovulation, which then stimulates the ovaries to release estradiol and progesterone. Amenorrhea, the absence of a menstrual cycle, is caused by the suppression of the hypothalamus secreting GnRH. This leads to no release of LH or FSH, no stimulation to the ovaries, no release of estradiol or progesterone, and no menses. It has been found that long term amenorrhea, especially in adolescents, can lead to cardiovascular, bone density, and psychiatric issues in the future.
One of the most important hormonal factors responsible for bone health is estradiol. By stimulating osteoblast (bone-building) activity, estrogen promotes the formation of certain growth factors including transforming growth factor beta (TGF-β), insulin-like growth factor 1 (IGF-1), and bone morphogenetic protein 6 (BMP6) (Meczekalski, et al, 2010). But if estrogen is never being released then bone formation and growth can’t continue. So, those who experience absence of a menstrual cycle for an extended amount of time are at increased risk for bone disorders like osteoporosis or osteopenia.
At the vascular level, estrogen-mediates inflammation, oxidative stress and over long-term estrogen increases endothelial-cell growth and inhibits smooth muscle cell proliferation (Shufelt, et al 2017). A study done on monkeys found that those who had low levels of FSH, LH, estradiol, and progesterone were at higher risk for cardiovascular disease. But when they were supplemented with oral estradiol their risks decreased. Further supporting the importance of having regular menses.
The presence of estrogen influences many areas of the brain including to the hypothalamus, cerebellum, nigrostriatal and mesolimbic system, amygdala, hippocampus, cerebral cortex, and brainstem (McEwen, et al, 2012). It has been found that estradiol is linked with levels of serotonin and dopamine, which is related to depression. Women with amenorrhea have significantly higher depression scores, greater anxiety, and increased difficulty coping with daily stress as compared to healthy controls (Shufelt, et al 2017). While there are many factors that can influence one’s mental health, it appears that one of the easiest ways to maintain it is by having regular menses.
While it may be advantageous to not have a menses when exercising, it is not advisable to suppress it long term, especially in adolescence. Many females start birth control in adolescence, which could lead to an ethical discussion involving the principals of beneficence and non malfeasance, as birth control has been known to suppress mensuration.
References
Golden NH, Carlson JL. The pathophysiology of amenorrhea in the adolescent. Ann N Y Acad Sci. 2008;1135:163-78. doi: 10.1196/annals.1429.014. PMID: 18574222.
Meczekalski B, Podfigurna-Stopa A, Genazzani AR. Hypoestrogenism in young women and its influence on bone mass density. Gynecol Endocrinol. 2010 Sep;26(9):652-7. doi: 10.3109/09513590.2010.486452. PMID: 20504098.
McEwen, B. S., Akama, K. T., Spencer-Segal, J. L., Milner, T. A., & Waters, E. M. (2012). Estrogen effects on the brain: actions beyond the hypothalamus via novel mechanisms. Behavioral neuroscience, 126(1), 4–16. https://doi.org/10.1037/a0026708
Shufelt, C. L., Torbati, T., & Dutra, E. (2017). Hypothalamic Amenorrhea and the Long-Term Health Consequences. Seminars in reproductive medicine, 35(3), 256–262. https://doi.org/10.1055/s-0037-1603581