What is the female athlete triad?

The female athlete triad involves three interrelated factors: energy availability, menstrual function, and bone mineral density (BMD). We explore each factor in this extract from Fundamentals of Sport and Exercise Nutrition.

Each of these factors is highly influenced by both diet and exercise. Each factor develops along a spectrum from optimal to dysfunctional. Ideally, each female athlete would have optimal energy availability, normal menstruation, and optimal bone health. Unfortunately that’s not always the case, and female athletes may develop low energy availability, disrupted menstrual function, and low bone mineral density. Each of these conditions is detrimental, and because they are interrelated they can have far-reaching effects on the athlete’s health.

Energy availability refers to how well caloric intake is matched with energy expenditure and is an important factor in the triad. When caloric intake is substantially and persistently below what is needed for performing exercise training, then normal body functions are affected. Low energy availability may be the result of disordered eating or an eating disorder. However, it may be due to inadvertently eating too few calories. For example, an athlete may lack appetite after rigorous training, and sleeping may be a higher priority than eating. Low energy availability may also be a result of internationally eating too few calories in an effect to keep from gaining weight. Regardless of the cause, low energy availability forces the body to adapt to a persistent semistarvation state, which results in hormonal imbalance and other problems.

Menstrual function is another factor in the triad. Menstrual hormones, such as oestrogen and luteinising hormone, are affected by low energy availability. Athletes may be anywhere on the menstrual function spectrum from normal menstruation, known as eumenorrhea, to intermittent menstruation to amenorrhea, a lack of menstruation. Low oestrogen also negatively affects bone mineral density, the third component of the triad. Low bone mineral density is a risk factor for developing osteoporosis. Although osteoporosis is most often associated with women over age 50, it can develop in athletes at a young age. Some female athletes, such as long-distance runners, have been diagnosed with osteoporosis in their mid- to late-20s.

The three factors in the triad move from optimal to less optimal to dysfunctional within different time frames, so it is possible that an athlete with low energy availability has not yet developed one of the obvious dysfunctional conditions, such as lack of menstruation.

Screening for the female athlete triad should be part of a female athlete’s physical exam. Although any female can be at risk for low energy availability, menstrual dysfunction, and low bone mineral density, distance runners, ballet dancers, swimmers, gymnasts, and lightweight rowers are known to be at higher risk because low weight is a factor in appearance and performance. The reversal of low energy intake is important for the athlete’s health. If calories are being restricted because of disordered eating, then the athlete should be referred to treatment, including psychotherapy, because the reasons for restricting food intake may be deep-seated and not easily resolved. A sport dietician can help an athlete develop strategies to match food intake with energy expenditure even on busy training days. Menstrual irregularities and low bone mineral density are medical problems that need treatment by a physician.

Learn more in Fundamentals of Sport and Exercise Nutrition.