The Female Athlete Triad
What hormonal imbalance looks like
So far in Performance Edge, we have learned a lot about female physiology! In earlier posts we have discussed the menstrual cycle, what it means when the menstrual cycle changes as well as the important role that the stress response plays in our physiologic balance and as the driver of physical performance.
Today we are putting it all together to better understand the Female Athlete Triad - a constellation of physiologic processes that occurs as a result of a sustained imbalance among fueling, recovery, and training.
The Female Athlete Triad was originally defined in an American College of Sports Medicine position statement published in 1972. It describes a condition in physically active young women that includes low energy availability (LEA), menstrual cycle dysfunction, and low bone mineral density (BMD). When the caloric amount and/or types of macro and micronutrients do not adequately fuel an athlete’s physical expenditure, this is referred to as low energy availability (LEA). When LEA is sustained, there are significant, detrimental physiologic changes that occur and are referred to as relative energy deficiency in sport or RED-S.
Today we are going to review the details of this triad of physical findings, how to identify them, and things you can do to keep your body in balance and at peak performance.
The Triad
1 -Low Energy Availability (LEA)
The imbalance between fueling and physical expenditure comes in many forms and is not as simple as just “calories in and calories out”. Nutrients are just as important as energy. Below are some examples of how fueling imbalance can happen:
Inadequate caloric intake - Although this is not the whole story, it plays an important role. The nutrients we consume are the “potential energy” the body uses to carry out its functions. A 9V battery cannot power your Tesla.
Imbalance of macronutrients - The Human body requires carbohydrates, proteins, and fats to function optimally.
Carbohydrates are the main source of energy or “battery juice” for cells to function. When carbohydrate is insufficient, the body starts breaking down proteins, most notably muscle tissue, to obtain the energy it needs to function.
Proteins provide the “building blocks” for muscle, bone, and other bodily tissues. If protein is insufficient, tissues cannot repair properly. Muscle, bone, tendons, and ligaments suffer creating inflammation that further limits the ability of the body to repair and prepare for the next physical task.
Fats serve as the structural component of cellular membranes of every cell of the body and serve as long-term storage of potential energy. When fats are insufficient, cellular integrity suffers resulting in skin rashes, hair loss, and potentially immune system dysfunction.
Nutrient timing - The body needs fuel when it needs it! There is a “baseline” need at rest to perform “routine” bodily functions and an acute need when a physical task is upon us. To satisfy both needs, a consistent, continuous supply of nutrients is needed for optimal function, with extra nutrition surrounding physical tasks.
One large meal during the day - Our professions and life, in general, can make it difficult to eat multiple times throughout the day. This creates a situation where the body dials down metabolic processes during the hours without food to conserve energy. Even when caloric and macronutrient volumes and ratios are appropriate, when consumed only once during the day, the body has not had access to those nutrients during the times when it needed them. So the body thinks that it is starving even when total caloric and macronutrient intake in that one meal was appropriate.
Insufficient fuel surrounding training - Training sessions for athletes, high-performing service processions and the military can be prolonged and intense, and thus have special nutritional considerations and fueling needs. Again, the body needs fuel when it needs it. Depending on the type of training and duration, proteins, carbohydrates, and fats are needed prior to, often during, and after training. It is critical for the body to have access to the nutrients it needs to fuel these intense sessions and recover from them thereafter.
A word about fasting for active women - Don’t do it. Plain and simple. Dr. Stacy Sims nails this one in her blog post “Yes! You are an athlete. No! You shouldn’t practice Intermittent Fasting”. Intermittent fasting can be beneficial in the sedentary population for the management of obesity and metabolic disease. But the evidence suggests no significant benefit for women who consistently train and can potentially be harmful. This is because female hormonal physiology has built within it multiple endocrine pathways that sense energy availability throughout the body with safeguards to protect it as a top priority.
When energy needs are not met, it’s like a “five-alarm fire”. Muscle is sacrificed, menstrual cycles are suppressed, thyroid function dials down, the “fight-or flight” response is activated and cortisol levels rise. Performance and procreation take a back seat to the favor of restoring energy balance.
2 -Menstrual Dysfunction
This second element of the Female Athlete Triad is a direct result of the first. As we reviewed in “What does it mean when the menstrual cycle changes”, the menstrual cycle is a “vital sign” that reflects physiologic balance in a woman’s body. LEA and RED-S often lead to menstrual cycle changes because of sustained physiologic imbalances that result from inadequate fueling and chronic activation of the stress response pathway. This critical pathway is evolutionarily programmed to suppress reproductive function when the capacity for physical adaption (required for pregnancy, a triathlon, or other physical performance tasks) is suboptimal.
3 - Low Bone Mineral Density
This third element of the Female Athlete Triad is a direct result of the first and second elements, however, multiple endocrine pathways contribute to the balance of bone formation and resorption.
Menstrual cycle suppression - Bone mineral density is directly related to circulating estrogen, as estrogen is a bone-building hormone. When menstrual cycles are regular, there is cyclic production of estrogen by the ovary that regulates ovulation. When menstrual cycles are suppressed or absent, the cyclic production of estrogen is also absent leading to a shift in the balance away from bone formation.
Metabolic impact of LEA - As mentioned above, the female body sounds the alarm when energy availability is insufficient, impacting multiple endocrine pathways. Menstrual cycle suppression is one of these pathways, however, there are other metabolic pathways impacted by LEA.
The hormones Ghrelin and Leptin and Peptide YY (PYY) are secreted in the gastrointestinal tract in response to fat mass and energy availability. They regulate feeding behavior to achieve energy balance.
Oxytocin is a bone-building hormone that modulates metabolic rate as well as appetite. Night-time oxytocin levels tend to be lower in states of high energy expenditure. Lower levels of oxytocin in athletes whose menstrual cycles are absent have been associated with abnormal bone microarchitecture in non-weight-bearing bones such as the radius (forearm).
Insulin is a bone-building hormone that is responsible for the uptake of glucose in the peripheral tissues. Elite athletes with absent menstrual cycles have lower serum insulin concentrations compared to normally cycling athletes.
Building bone density is critically important in younger women, particularly those under the age of 30. Bone formation during these young adult years will determine peak bone mass. If the development of peak bone mass is compromised, this becomes a leading risk factor for developing osteoporosis and debilitating bone fractures later in life.
Tips for Avoiding the Female Athlete Triad
Track your menstrual cycle! Now, this does not mean you need to obsess over it like a food log - simply be aware of the interval of time between your cycles from the first day of one to the first day of the next. Consistency is most important +/- 3-4 days. Most women have menstrual cycle intervals of 28-32 days.
If you are missing menstrual cycles on more than one occasion in a 6 month period or notice more than 7 days of variation in cycle interval for 3 periods or more, contact your health provider for an evaluation.
For more information on the things that cause menstrual cycle irregularity, check out this previous post “What does it mean when the menstrual cycle changes?”.
Fractures. If you experience a fracture, contact your healthcare provider and discuss whether a bone density scan is appropriate. Even if you are pre-menopausal, special scaling (the Z-score) is used to determine if osteopenia or osteoporosis is apparent. The sooner this issue is identified, the more effective any interventions will be to slow bone loss or even rebuild lost bone density.
Seek the help of a sports nutritionist. Whether you are an elite or avid recreational athlete, food “relationships” can be complicated. Obsessing about “macros” and “clean eating” can be counter-productive psychologically, but a lack of awareness of the amount and types of fuel needed to perform is equally harmful. Finding that balance is critical and can be achieved with help from coaches and sports nutrition experts.
Communicate with your coaches and trainers. Just like it is important to keep your coach/trainer in the loop about physical injuries, it is equally important to inform them when your menstrual cycles have changed. It’s not the easiest topic to discuss, but your menstrual cycle is your most critical cue to your physical response to training and achieving your peak performance. If your periods disappear, your trainers and coaches need to know, and if they tell you “This is normal”, you need to get a new trainer/coach.
A Word About Body Image
One of the most common themes I have seen in my patients and clients is the significant impact of body image on eating and training behavior, which speaks directly to the energy balance we have been discussing.
Sadly, the societal definitions of and the pressure to attain the “ideal female body” are often in direct conflict with what the female body needs for optimal health and performance. These “ideals” are one-size-fits-all, no matter what your age, morphologic body type, sport, or profession. Women’s performance and health are anything but that.
Now, I’m not saying we shouldn’t want to look good. Taking pride in one’s appearance is a virtue. My beef is when these set “standards” jeopardize health and performance. Six-pack abs do not work for all athletes. Thighs that don’t touch in the middle don’t work for all athletes. D-sized breasts do not work for all athletes - my running is slow enough without them! My favorite one that plagues my generation is that “muscles are masculine” - which is the last thing any menopausal woman needs to hear as she loses muscle and bone mass by the day due to her changing hormones.
What has further complicated the issue is the lack of research that tells us how to achieve optimal energy balance in female athletes. For decades, the principles for training and fueling men have been applied to women for lack of meaningful research that applies specifically to women’s performance. Thankfully, this is changing and more and more attention is being paid to the physiologic differences between men’s and women’s physical performance and fueling requirements.
Although there is much work to be done, we have every reason to be optimistic as we see that the tide is changing with the more we learn about women’s unique physiology. So the key to success is keeping these complicated dynamics in perspective and prioritizing your health and well-being front and center, without compromise.