The Female Athlete Triad
The Female Athlete Triad was coined to describe the associations between energy availability, menstrual function and bone health, specifically bone mineral density (BMD). Each of these spectrum exists on a continuum between health and pathology, and the Triad is diagnosed in any exercising woman who exhibits signs and/or symptoms consistent with the pathological end (see purple triangle in Figure 1 below) of any one or more of these spectrums.
Prevalence and risk factors for low energy availability and disordered eating behaviours
Clinical eating disorders have been diagnosed in 25-31% of elite female athletes who participate in endurance, aesthetic and weight-class (i.e. lean build) sports. However, energy deficiency and subclinical disordered eating behaviours are NOT solely limited to women who participate in these sports. Rather, the numbers seem to be growing across a wide variety of sports as female athletes continue to pursue their sporting dreams on the national and international stage. Indeed, a recent study conducted by researchers at Austin State University (Texas) revealed a high prevalence of body image disturbances in female athletes in the mainstream sports of basketball, softball, volleyball, soccer, tennis and ice hockey.
While research may suggest that eating disorders and disordered eating behaviours are more prevalent in female athletes compared to non-athletes, this is not necessarily the case. In comparison to female athletes, exercising women report a higher incidence of dieting (22.1% vs. 51. 9%), drive for thinness (2.3% vs. 7.6%) and body dissatisfaction (16.6% vs. 31.6%).
Regardless of the mechanism by which low energy availability develops (i.e. inadvertent, disordered eating behaviours or eating disorders), chronic energy deficiency places female athletes and exercising women at-risk for menstrual disturbances, low bone mineral density and compromised cardiovascular function. Unfortunately, inadvertent low energy availability (i.e. without disordered eating behaviours or eating disorders) is difficult to research and so the true prevalence of female athletes and exercising women at-risk for an energy deficit and the Triad is likely under-estimated.
Predisposing factors for low energy availability and disordered eating behaviours in female athletes and exercising women include:
- Weight classifications in sports such as rowing, weightlifting and boxing prompt athletes to try to ‘make weight’ so they can compete in a lower weight class. Pathogenic weight control strategies such as fasting, fluid restriction, and the use of diuretics, laxatives, and vomiting are often used to achieve rapid weight loss in these sports. Coaches and trainers should discourage these weight-loss methods, even those that are embedded in the sport culture
- Coach and peer pressure within the sport (or parental, peer or partner pressure among exercising women)
- The correlation between low body mass and body fat and successful performance in certain sports (e.g. triathlon, distance running) has led many coaches and athletes to focus on weight control
- Judging criteria in some sports (e.g. figure skating, gymnastics) tend to be biased toward certain body types
- There are increasing expectations for female athletes to conform to a particular hyper-feminine and heterosexually attractive ‘image’ to meet the western sociocultural belief that being thin is a sign of success, and necessary to gain media attention and sponsorship deals. This places additional pressure on girls and women who participate in a wide range of sports
If you, as a coach, teacher, personal trainer, health professional, exercise leader and/or parent, identify someone who demonstrates symptoms associated with disordered eating behaviours, you will need to solicit help from a specialist familiar with eating disorders. Indeed, it would be a serious mistake to think that disordered eating in any woman (whether it be clinical or subclinical in severity) is acceptable and/or that she can manage her eating or body image issues on her own.
Rigorous exercise without adequate nutrition can affect the female reproductive system, as observed (in the more extreme cases) by menstrual disturbances. Amenorrhea is the medical term for the absence of a menstrual cycle. Amenorrhea is characterised by constant low levels of estrogen and progesterone and compromised luteinising hormone (LH) pulsatility. This suppresses follicular development, ovulation and luteal function. Amenorrhea can be classified as primary or secondary. Primary amenorrhea refers to girls whose menstrual cycles have not begun by age 15 years (particularly common among gymnasts and ballet dancers), and secondary amenorrhea refers to previously menstruating women who have an absence of menstrual periods for more than 90 days (i.e. at least three consecutive cycles).
Studies suggest the prevalence of secondary amenorrhea may exceed 65% in dancers and endurance runners compared to 2–5% in the general population. Primary amenorrhea may also be prevalent in more than 22% of cheerleaders, divers and gymnasts compared to 1% in the general population. However, less severe, yet still energy-related, menstrual disturbances are characteristic of both female athletes and recreational exercising women. Indeed, luteal deficiency or anovulation was found in 78% of regularly cyclic recreational runners in at least one menstrual cycle out of three.
Low bone mineral density
Bone strength and the risk of fracture depend on the density and internal structure of bone mineral and on the quality of bone protein. Bone mineral density (BMD) is assessed via dual-energy x-ray absorptiometry (DXA), with low measures suggesting high risk for bone fractures and osteoporosis. Since bone adapts in response to the loads placed on it, girls and women who participate in weight-bearing sports (e.g. running, dancing, basketball) typically have higher BMD than non-athletes. However, the prevalence of low BMD has been reported to range between 1.4–50% in exercising girls and women who are considered to be at risk for developing the Triad. It must also be noted that while sports like running and dancing may significantly load the leg and hip bones to increase or maintain their BMD, the bones of the upper body are not loaded in these sports. Fractures to the wrist and shoulder are common in women with low BMD and so weight-bearing activity that targets the upper limbs is also important for young girls to optimize peak bone mass and for pre-menopausal and menopausal women to help maintain BMD and thus reduce the risk of fractures.
Prevalence of the Female Athlete Triad
All three components of the Triad (i.e. low energy availability/disordered eating, menstrual disturbances and low BMD) may present in 4.3% of elite female athletes from a range of lean- and non-lean build sports, and 3.4% of age-matched women engaging in recreational exercise. Any two components of the Triad may also present in 5.4-26.9% of female athletes and 12.4-15.2% of women who engage in recreational exercise.
An important note is that low energy availability is routinely defined in studies by the presence of disordered eating behaviours. Yet numerous exercising women may also be at-risk for an energy deficit via inadvertent or purposeful means that are independent of disordered eating behaviours. In addition, self report data collection is not able to identify less severe menstrual disturbances, such as luteal phase defects and anovulation. Thus, the prevalence of women who have or are at-risk for developing the Triad is likely to be under-estimated. It is important to highlight that prevention of one or more of the Triad components should be geared towards all exercising girls and women and not just athletes.
In the remainder of the ‘Get Educated!’ section we discuss each of the three main components of the Female Athlete Triad in more detail, particularly as they relate to energy deficiency. We also expand upon the Triad to discuss some of the socio-psychological factors, and cardiovascular risks that also need to be added to the conversation about the long-term health of female athletes and exercising women. So keep reading!