For a review of the first part, check it out here!
Low Energy Availability (With or Without an Eating Disorder)
Energy availability is defined as “dietary energy intake minus exercise energy expenditure” (1). This is the amount of energy remaining for all other physiological functions of daily living, after energy requirements for exercise training has been removed. Optimal energy is when there is adequate energy remaining for the remaining body functions. Low energy availability may or may not be a result of disordered eating such as anorexia nervosa, bulimia nervosa, binge eating disorder, etc. For example, think of a 1st year university student, who is living away from home to continue their post-secondary athletic career. Living on their own for the first time, they may not understand the importance of proper nutrition or even how to cook nutritious meals. Combine that with rigorous training demands, their body is most likely not getting enough energy through a proper well-balanced diet, and any energy they do consume (ex. Microwaveable Kraft Dinner) is going straight to their sport, leaving little to none for daily bodily functions.
As stated previously, when energy levels are low, this leads to less energy available for the remaining body functions. This can lead to hormone imbalances causing menstrual disturbances, and altered bone formation, both a component of the Female Athlete Triad.
Poor nutrition, low caloric intake, high-energy demands, physical and emotional stress, and low body fat percentage can all lead to hormonal changes. This may end up causing an irregular period, cessation of the menstrual period all together (amenorrhea), or Functional Hypothalamic Amenorrhea. Amenorrhea is defined as the absence of a menstrual cycle for > 90 days and is divided into Primary and Secondary Amenorrhea. Primary Amenorrhea is the absence of the first period by age 15, while Secondary Amenorrhea is the absence of a period for >90 days. Functional Hypothalamic Amenorrhea (FHA) can be a primary or secondary amenorrhea that is caused by low energy availability. FHA can be caused by weight loss, stress, or excessive exercises, and result in an estrogen deficiency. This can lead to a number of health issues including infertility, low bone mineral density, fractures, anxiety and depression.
Low Bone Density
Bone health is extremely important as we get older, therefore building strong bones at a young age is necessary to provide a stronger foundation as we age. Low energy expenditure plays a big role in bone mineral density. A randomized control trial found that when caloric intake was restricted to < 30kcal/kg, it had a negative effect on hormones (2). This led to an estrogen deficiency, which can negatively impact bone formation (2). When bones weaken, it increases the chance of stress fractures, and if not treated, may cause osteoporosis later on in life.
The next write up with include Treatment and Management of the Female Athlete Triad.
~ Alex Wojcichowsky, Physiotherapist
1. Nattiv, A., Loucks, A. B., Manore, M. M., Sanborn, C. F., Sundgot-Borgen, J., Warren, M. P., & American College of Sports Medicine (2007). American College of Sports Medicine position stand. The female athlete triad. Medicine and science in sports and exercise, 39(10), 1867–1882. https://doi.org/10.1249/mss.0b013e318149f111
2. Female Athlete Triad. (2020, August 13). Physiopedia, . Retrieved 04:41, September 9, 2020 from https://www.physio-pedia.com/index.php?title=Female_Athlete_Triad&oldid=245810.
3. Loveless, M. B. (2017). Female athlete triad. Current Opinion in Obstetrics and Gynecology, 29(5), 301-305.
4. Hobart, J. A., & Smucker, D. R. (2000). The female athlete triad. American family physician, 61(11), 3357-3364.
5. NCAA coach handbook: Managing the Female Athlete Triad. https://athletewellness.uncg.edu/wp-content/uploads/2014/05/Coaches-Handbook.pdf