"Lost"

Female athletes endure more stress than men. There is no argument there. The cycle of hormones during a menstrual cycle puts their bodies and minds to the test. If that wasn’t enough, the situation changes week to week with different levels of these hormones causing different physiological conditions. 

The menstrual cycle has two distinct phases separated by ovulation. Long story short, there is the follicular phase that lasts roughly two weeks, ovulation, and then the luteal phase that lasts another roughly two weeks. The high levels of hormones, specifically progesterone, keeps the corpus luteum or endometrial lining of the uterus nourished until implantation. If implantation does not occur and human chorionic gonadotropin is not released by the fetus, the corpus luteum degrades which gives rise to vaginal bleeding known as one’s “period” (Reid, 2017).

What happens to extreme female athletes? Did they just… lose their period? No, of course, it’s more complicated than that. The phenomenon is known as athletic amenorrhea (Pauli and Berga, 2010). It is believed that the stress induced by extreme athletics causes allostasis or the change of physiological setpoints of homeostasis. This change causes less overall drive in the hypothalamic-pituitary- axis (HPA) to produce a large enough spike in luteinizing hormone (LH) and follicular stimulating hormone (FSH) to stimulate ovulation (Pauli and Berga, 2010). No ovulation leads to no progesterone production which leads to malnourishment of the corpus luteum, which of course means it won’t degrade and cause a period.

Why? What is the physiological adaptation to limit the drive of GnRH and therefore LH and FSH from the hypothalamus and anterior pituitary, respectfully, needed to ovulate and reproduce? The literature suggests an unfavorable caloric and lipid profile (Rickenlund et al., 2005). In my eyes, this means the homeostatic mechanisms in the body believe that this athlete is not healthy enough to nourish and care for a second body. Healthy is a loose term because some might think a low body fat percentage and the capability of extreme endurance performance is the healthiest one can be!

To return to the normal cycle, the most suggested mechanism is to choose a less demanding sport… which every healthcare professional should refrain from saying unless you want to ruin the dreams of your female athletes.

Pauli, S. A., & Berga, S. L. (2010). Athletic amenorrhea: energy deficit or psychogenic challenge?. Annals of the New York Academy of Sciences, 1205, 33–38. https://doi.org/10.1111/j.1749-6632.2010.05663.x

Reid RL. (2017). Premenstrual Dysphoric Disorder (Formerly Premenstrual Syndrome) In: Feingold KR, Anawalt B, Boyce A, et al., editors. South Dartmouth (MA): MDText.com, Inc.; 2000-.

Rickenlund, A., Eriksson, M.J., Schenck-Gustafsson, K., Hirschberg,, A.L. (2005). Amenorrhea in Female Athletes Is Associated with Endothelial Dysfunction and Unfavorable Lipid