htxag09 said:
I feel like a lot of this science is fairly new and gaining momentum. Most new garmin watches now have cycle tracking and recommend how to adjust workouts. Note, as I'm a dude I have no experience with any of it, just found it odd when they started advertising. Hadn't looked into it anymore or read anything else about it until this thread/article.
Woman here. The science isn't new. It's been known for a long time that a variety of things cause amenorrhea (the absence of menstruation), the most obvious one being pregnancy. It's not a disorder in and of itself, but a symptom of something else.
When it comes to people who are extremely physically active/fit, it can be due to excessive exercise, not taking in enough calories, or low body weight and/or body fat percentage. Something like 60+% of ballet dancers and long distance runners experience it. Young girls who are elite athletes and dancers also see a delay in the initial onset of their cycles, sometimes by several years compared to the average.
The only reason you see it "advertised" now is because the fitness trackers want to sell women a device they can use to "conveniently" track their cycle, just like you can track your steps, calorie intake, water intake, etc. Prior to wearable devices, women just did this with a calendar or a journal.