My college coach told me it's OK to lose my period

And you’re so male. Completely disregarding basic science and spewing absolute BS. Please link this research pointing to the fact that “periods reduce athletic performance.” This is typical LetsRun nonsense, and this thread is not even about running anymore.

Wow, I learned so much from this thread! Thank you to all the LR doctors for weighing in!

Sorry for being ignorant, but how would a woman prevent this? Would she just have to give up running forever? As others have said, it happens on low mileage. And does this occur in other sports as well that train hard, like ufc or basketball? I see athletes giving birth all the time so I didn't really know this was a thing.

I know the Mary Cain fan club is going to hate me for saying this, but I've had this same conversation with a athlete before. As a coach, when you are asked a question, you answer it to the best of your ability and in the best interest of the athlete. In my particular case and that time, I stated I didn't know much about female reproductive / endocrine health and referred the athlete to someone that knew more. With that said, I now know that that not having a period for sustained period of time is not good for you; however, I am pretty certain elite level endurance athletes usually don't have a normal period cycle in the prime of their careers.

There's nuance to all this. Losing your period is common, and from a health perspective is indicative of problems. The problems can range from "unrelated to running health" to "very interrelated to running health." And just because RED-S is common doesn't mean that it is ideal for continuing to improve as a distance runner.

Irregular or uncommon periods is not *always* indicative of too high of a training load or poor nutrition. An example earlier on this threat was a girl who only had a period 3x per year. This is common for polycystic ovarian syndrome. PCOS is a hormonal disorder that is associated with a bunch of other health risks and risks for infertility, but running less is not going to make that girl's periods more regular. PCOS is also very common and affects something like 10-20% of women. That's the roll of the dice for genetics and not necessarily a sign of too high of a training load. There's not really much to do in that case other than manage symptoms (often with hormonal birth control) until that girl wants to get pregnant later in life. There are other issues like endometriosis as well that can lead to irregular periods that are not necessarily related to training load.

Certain forms of birth control (especially lower doses of estrogen) and the hormonal IUD can result in no periods, but this is not a sign of RED-S (ALL birth control masks ovulation as a sign that you are not in RED-S and pills that have a bleed are just a hormone withdrawal bleed). Girls who use to use birth control (for contraception, or for management of issues like PCOS or endometriosis) should be extra careful with nutrition since they can't use the cycle as a signal to monitor.

Missing one or two cycles here and there isn't necessarily a problem (although it can be a sign to be more contentious of nutrition and recovery) and it's not terribly uncommon when adjusting to a new training load. But if you go into a prolonged RED-S stage, you are asking for dealing with a nasty injury cycle in the far off but not too far off future (approximately 6 months-1 year). Sometimes that injury cycle takes years to climb out of (we are seeing this with Allie O and Molly Seidel) and sometimes it ruins careers.

There is more than just calories. There can be tweaks like eating enough healthy fats to support hormonal health, eating enough carbohydrates to avoid long bouts of low glycogen, making sure you eat breakfast even before easy runs to keep cortisol from building up too much, and avoiding within day energy deficits (like eating snacks throughout the day rather than not eating all day and eating a huge dinner). These things are just generally good for recovery anyway.

Just because it's common doesn't mean that it's beneficial to training to have your hormones messed up. Most runners at some point have low ferritin, especially when training at altitude. Talented people are so talented they often can get away with being suboptimal for a while. Everyone knows a talented runner who ran ok to well for a while with low ferritin levels. That doesn't mean they aren't faster when their ferritin levels are more optimized.

So seeing a doctor can help disentangle whether the menstrual issues are unrelated or caused by training (not always clear cut, but sometimes clear cut). Prolonged lack of menstruation absent issues like PCOS or endometriosis is a problem that should be addressed, both for running performance and general health.

Some women are more prone to their hypothalamus shutting off menstruation under periods of physical stress than others and can handle being leaner than others. This unfortunately is part of the genetic ability to handle training load. Just as some of us are born with stronger bones than others or more repairable tendons, some of us have more delicate endocrine systems than others. However this shouldn't be assumed is the issue unless all efforts to correct common fuelling issues are addressed. Also sometimes being extra prone to menstruation shutting down without overly restrictive eating can be signs of other undiagnosed issues like celiac or thyroid issues. These can be corrected with appropriate diet or medication and are also likely to improve running performance once addressed.

If lack of periods are happening at low mileage there can be a few things:

1. She's not eating enough/a diet that means her dietary needs/timing her nutrition appropriately, even if it's unintentional. College students are busy and many naturally thin people are not good at adjusting caloric intake for increased activity levels. Eat more, but also look at *what* they are eating. Are they eating enough protein, carbs, and healthy fats? Constant, prolonged mild glycogen depletion is bad for women's hormones. Low fat is also bad for women's hormones. Not enough micronutrients like vitamin D, vitamin B, or iron is also bad for hormones. Having large "within day" energy deficits (having a big workout in the morning, eating a granola bar and skipping lunch, and then not having a real meal until dinner) is also dis-regulating to hormones. There is a lot you can monitor with diet. Both how many calories, what they are eating, and when they are eating surrounding workouts can all be part of the picture. Addressing this helps recovery and absorbing training load.

2. Does she have other hormonal issues such as PCOS or endometrosis? These are health issues, but they aren't caused by running or running training. They are just the genetic luck of the draw. If that's how she is, then lack of periods are not a sign of overdoing it. One of the best ways to mitigate those symptoms is hormonal birth control. These issues will cause likely issues with fertility later in life, but not anything that can be avoided with avoiding running training. Going to a doctor and getting this checked out is a good idea, just for general health. Figuring out the best way to manage symptoms (e.g. finding the right hormonal BC) is going to be the best for her running and the best for her health.

3. Is it some other health related issue? Could be undiagnosed celiacs, some autoimmune diseases, thyroid issues. Those need to be addressed for both running and health anyway. Medication or dietary fixes can help, then she will be absorbing nutrients better and the cycle might regularize.

So I would recommend if a woman is losing a period at low mileage, they do a combination of evaluating diet and going to see a doctor to determine if there are other hormonal or health issues.

And yes, this happens with other sports.

So I brought this to our trainer and they seemed pretty upset while scheduling me for a doctors appointment. Now I'm worried they are going to pull me and any other women that lost their period so kinda regretting bringing it up. And I can just hear coach saying "you don't care about how this effects the rest of the team" and "our doctor doesn't understand what it takes to be an elite DI athlete" right now. Guess that's why we are division 2? Talking to alumni, I guess its just always been like this here (everyone lost theirs while training in college) but been discouraged to talk about. Thanks for the positive female voices here tho.