Yesterday I posted on the importance of incorporating chocolate chip cookies into your diet. I promised I’d continue on this topic of energy availability. And so here we are now, diving into something a little more taboo– missing your period (due to sports/training). Lauren Fleshman and Stephanie Bruce have been vocal on social media about this issue. These women make me so happy–they’re getting the conversation (and hopefully the science) moving. But I think we all need to dive deeper into the physiological consequences of a missed period.
Why do we lose it? Yes we, I’ve been there too. Missing a period stems from the body not receiving enough energy (calories) to keep up with demands put on it. The body needs energy just to keep all the systems functioning. And when you are exercising, these energy demands are high! Essentially, if the energy taken in (calories consumed) is not as high as the energy expended (calories burned), then the body is in “negative energy balance“. If the body is not receiving enough energy, the first thing to shut down is reproduction. Goodbye period.
So what are the consequences? The Female Athlete Triad is a syndrome in where low energy availability results in a disrupted menstrual cycle (amenorrhoea or oligomenorrhoea), and low bone mineral density (BMD). The figure below shows how the female athlete triad works along a continuum, and people can fall at various points along each of the three lines.
But my bones are fine. So I’m fine. Not so fast. Looking at the diagram above of the Female Athlete Triad, it might be easy to think the long term consequences of osteoporosis aren’t in my cards because I’ve never had a bone injury or I’ve had my bones checked and my bone mineral density is good. But not getting enough energy can span a larger range of health consequences. The Reduced Energy Deficiency in Sports syndrome (or RED-S) refers to impaired physiological function beyond the triad (and now reminds our male counterparts they’re not immune from this either). The little red triangle in the figure below shows what we generally think of as the consequences of reduced energy. But in actuality, if you are not eating enough, the effects on your body are alarming! Your immune system might be weaker and now you’re catching every little bug that goes around. Your GI tract is constantly upset. More endocrine disruptors meaning your hormones are out of whack. Hematological (blood) disruptions affecting your iron, hematocrit, hemoglobin–all things that any top endurance athlete needs functioning optimally! Being in a chronic negative energy balance can lead to issues such as anemia, chronic fatigue, and depression.
What this boils down to: It’s not missing the period that’s detrimental, it’s what your body is trying to tell you, “Hey I don’t have enough energy available to me!” It’s a red flag you should take very seriously. Regardless, if you think you feel fine, the longer you spend in negative energy balance the more detrimental effects. These are things that you might not even realize are the result of a lack of energy–your personal life, relationships, academics, work, etc. SERIOUSLY. Read all of those colored balloons below!
You have to lose your period if you want to win. The idea that you have to lose your period to get lean and in race shape is ridiculous. First, if you do lose your period because you are not getting enough energy in, then you are opening yourself up to a whole host of other potential issues. You can’t train if you’re injured or sick. Plus, psychological distress such as depression and anxiety itself will impair your ability to train, and recover (as well as being a generally pleasant person to be around). A recent case study published  showed an elite female 1500m runner’s body composition seasonal fluctuations over the course of 9 years. I think most endurance athletes know their body weight cycles. We weigh less during the competitive season and more during the off or preparation season. While I don’t think there is much (if any) research on how to do this properly, if you are missing your period, then you’re cutting back too much and embarking on something dangerous.
Bottom line: If you are training hard and miss your period. Tell someone, your coach, nutritionist, doctor.
 Joy, E., De Souza, M. J., Nattiv, A., Misra, M., Williams, N. I., Mallinson, R. J., … & Barrack, M. (2014). 2014 female athlete triad coalition consensus statement on treatment and return to play of the female athlete triad. Current sports medicine reports, 13(4), 219-232.
 Mountjoy, M., Sundgot-Borgen, J., Burke, L., Carter, S., Constantini, N., Lebrun, C., … & Ljungqvist, A. (2014). The IOC consensus statement: beyond the female athlete triad—Relative Energy Deficiency in Sport (RED-S). Br J Sports Med, 48(7), 491-497.
 Stellingwerff, T. (2017). Case-Study: Body Composition Periodization in an Olympic-Level Female Middle-Distance Runner Over a 9-Year Career. International journal of sport nutrition and exercise metabolism, 1-19.