Chronic low energy availability can have significant effects on student-athlete health and physical performance, particularly when a clinical eating disorder is present. Although it may inadvertent, intentional or psychopathological, low energy availability plays a causal role in the induction of exercise associated menstrual disturbances. Chronically low estrogen levels associated with prolonged suppression of the menstrual cycle can negatively impact musculoskeletal and cardiovascular health. Low energy availability can also have negative musculoskeletal effects independent of low estrogen levels. Other medical complications of Triad disorders can extend to the hormonal, gastrointestinal, renal and the central nervous system.
Psychological Effects: Low energy availability in the Female Athlete Triad may be a consequence of inadvertent dietary restraint, excessive energy expenditure, and/or intentional dietary manipulation in the setting of an eating disorder (ED). A majority of females with an ED also suffer from a co-morbid affective disorder such as depression and anxiety. A majority (50 to 75 percent) of patients meeting DSM-V criteria for anorexia nervosa or bulimia nervosa have a concurrent mental health diagnosis. In addition to depression and anxiety, patients with ED may struggle with obsessive-compulsive disorder (41 percent), substance abuse (30 percent) and personality disorders (40to 60 percent). Rates of suicide among ED patients are more than triple that of age-matched healthy controls; thereby, necessitating a comprehensive multidisciplinary intervention. It is important to note that depression is not only a risk factor for ED, but can also be a consequence of weight loss and malnutrition. The prevalence of psychiatric disorders in athletes affected by the Triad remains unknown. Moreover, more research is warranted on the course and outcomes of treatment for athletes with co-morbid psychiatric disorders.
Gynecological Effects: The effect of low energy availability on reproductive function is mediated centrally at the level of the hypothalamus in the brain. Decreased central drive to the ovaries suppresses follicular development, ovulation and luteal function. In the case of amenorrhea, ovulation does not occur and thus a woman is transiently unable to conceive. The return of ovulation may occur prior to the onset of menses and thus the absence of menses should not be interpreted as reflecting the inability to conceive if a woman is recovering from menstrual cycles being absent. More subtle menstrual disturbances such as short luteal phases and luteal phases associated with reduced concentrations of progesterone may also be associated with a failure of implantation. Chronically low estrogen is associated with vaginal dryness, decreased libido, impaired cognitive function and low bone mineral density (BMD).
Musculoskeletal Effects: The most concerning morbidity of the Triad is low BMD associated with impaired bone structure and decreased bone strength. Additionally, low rates of bone accrual during puberty - a time when bone accrual is typically at its peak - may jeopardize attainment of peak bone mass in early adult life, which is an important determinant of bone health and fracture risk in later life.
Low BMD predisposes Triad student-athletes to fractures. Investigators have demonstrated an increased prevalence of stress fractures in amenorrheic athletes compared with athletes who get regular periods. Amenorrheic athletes also demonstrate a loss of the beneficial effects of weight-bearing exercise on bone strength that is observed in athletes with regular menstrual cycles at weight-bearing sites of bone. Although genetic, hormonal, metabolic, biomechanical, musculoskeletal, training, and nutritional factors play a role in bone stress injuries, studies have shown a strong association between the prevalence of one or more Triad components and bone stress injuries. In a recent study of exercising girls and women the risk of a bone stress injury increased from 15 to 20 percent with a single risk factor to 30 to 50 percent when two or more risk factors were present. Amenorrheic athletes have a relative risk that is four to five times greater than that of regularly menstruating athletes.
Cardiovascular Effects: Chronically low estrogen can negatively impact blood cholesterol levels and the ability of blood vessels to dilate. More research is needed to understand the long term health consequences of these cardiovascular changes. In the face of chronic low energy availability, especially in association with an eating disorder, electrocardiographic abnormalities, bradycardia, and postural hypotension have been reported. These latter changes are clinically relevant and could impact the proper functioning of the heart.
Nutritional Effects: Chronic low energy availability is associated with both macro- and micronutrient deficiencies. Female student-athletes commonly display inadequate intakes of total energy, carbohydrates and protein. Micronutrient deficiencies of iron, calcium and zinc have also been documented. Inadequate energy intake is often associated with higher drive for thinness and body dissatisfaction. However, reduced energy intake may be inadvertent due to an appetite suppressive effect of exercise.
Exercise Performance: Bone stress injuries sideline female student-athletes and as such reduce competitive performance. Poor sport performance has been documented in junior elite swimmers who exhibited ovarian suppression when compared to their cyclic counterparts. Chronically low estrogen may also impact muscle blood flow by causing impaired arterial dilatation, potentially leading to poor exercise performance or the induction of fatigue.
About the Female Athlete Triad Coalition
The Female Athlete Triad Coalition, a non-profit 501(c)(3) organization, represents key medical, nursing, athletic, and sports medicine groups, as well as concerned individuals who come together to promote optimal health and well-being for female athletes and active girls and women. The Coalition strives to prevent the Female Athlete Triad through advocacy, education, international leadership, public policy and research. Formed in 2002, the Female Athlete Triad Coalition is a group of national and international organizations dedicated to addressing unhealthy eating behaviors, hormonal irregularities and bone health among female athletes and active women. For more information, visit www.femaleathletetriad.org. The Consensus Paper was sponsored by the Female Athlete Triad Coalition: An International Consortium, and endorsed by Female Athlete Triad Coalition, American College of Sports Medicine and the American Medical Society for Sports Medicine.
About Nancy I. Williams, Sc.D., FACSM
Nancy I. Williams Sc.D., FACSM is a Professor of Kinesiology and Physiology and is currently the Head of the Department of Kinesiology at The Pennsylvania State University. She is a Past President of the Female Athlete Triad Coalition and a Co-Director of the Women's Health and Exercise Laboratory. Dr. Williams’ research has focused on the interrelations between energy balance and reproductive function and the underlying physiological mechanisms for these interactions. Dr. Williams has published over 75 peer reviewed papers, book chapters, monographs and letters to the editor.