Mary Jane De Souza

The etiology of amenorrhea in exercising women is linked to a mismatch between caloric intake and high levels of exercise energy expenditure that results in a chronic energy deficit. This in turn stimulates compensatory mechanisms such as weight loss, metabolic hormone alterations, or energy conservation that subsequently causes a central suppression of reproductive function and concomitant hypoestrogenism. This suppression of reproductive function is associated with stress fractures, loss of bone mineral density, the failure to achieve peak bone mass, osteopenia, and osteoporosis. It has generally been accepted that the chronic hypoestrogenism is the major cause of bone loss in exercising women. However, the effects of food restriction and energy deficiency on bone mineral density likely represents an estrogen-independent mechanism for bone loss that involves some of the metabolic-related hormones altered with exercise-associated amenorrhea. These hormones (IGF-1 and leptin) play an important role in modulating bone turnover and bone mineral density in these women.

Amenorrhoea associated with reduced caloric intake and strenuous exercise leads to hypoestrogenism and is associated with clinical manifestations that include disordered eating, stress fractures, osteoporosis, and, as recently reported, a potential increase in the risk of premature cardiovascular disease. Disordered eating, menstrual irregularities and bone loss comprise the clinical condition known as the ‘female athlete triad’. The aetiology of the triad is linked to a high prevalence of disordered eating and cognitive restraint. This results in inadequate caloric intake for high exercise energy expenditures that leads to energy deficiency. This in turn stimulates compensatory mechanisms, such as weight loss or energy conservation, subsequently causing a central suppression of reproductive function and concomitant hypoestrogenism. Because the aetiology of menstrual disturbances and the female athlete triad is causally linked to energy deficiency, there is no justification for fears that exercise itself is unhealthy for women. However, improved detection, monitoring, and treatment of all components of the triad in exercising women should be emphasized. This paper critically reviews the physiological aspects and clinical sequelae of energy deficiency and hypoestrogenism associated with the female athlete triad in exercising women.

Recent findings support a role for ghrelin in the regulation of energy homeostasis and possibly reproductive function. The primary purpose of this study was to test whether differences in fasting ghrelin levels exist in exercising women with differing menstrual and metabolic status. Menstrual cycle status was defined as sedentary ovulatory (SedOvul; n = 10, cycles = 26), exercising ovulatory (ExOvul; n = 11, cycles = 22), exercising luteal phase defect/anovulatory (ExLPD/Anov; n = 11, cycle = 27), and exercising amenorrheic (ExAmen; n = 8, cycle = 16). Subjects were 27.7 +/- 1.2 yr of age, weighed 60.2 +/- 3.3 kg, and had menstrual cycle lengths of 28.4 +/- 0.9 d. Blood was collected during the follicular phase (d 2-9) of each menstrual cycle and analyzed for total ghrelin, insulin, total T(3), and leptin. Ghrelin was significantly elevated by approximately 85% in the ExAmen category (725.5 +/- 40.8 pmol/liter) when compared with all other categories (P < 0.001; SedOvul = 393.6 +/- 32.0 pmol/liter, ExOvul = 418.9 +/- 34.8 pmol/liter, and ExLPD/Anov = 381.1 +/- 314 pmol/liter). Leptin levels were lower in all groups vs. SedOvul (P < 0.001). Insulin was lower in both the ExLPD/Anov and ExAmen categories vs. SedOvul and ExOvul (P < 0.018), and total T(3) was lower in ExAmen compared with all other groups (P < 0.001), with concentrations in ExLPD/Anov and ExOvul exceeding those in SedOvul (P < 0.05). These data clearly indicate a metabolic hormonal profile consistent with chronic energy deficiency in exercising women across a range in menstrual status and introduces ghrelin as a potential supplementary indicator that uniquely discriminates amenorrheic athletes from athletes with other menstrual disturbances.

In premenopausal women, the most severe menstrual dysfunction is amenorrhoea, which is associated with chronic hypoestrogenism. In postmenopausal women, hypoestrogenism is associated with a number of...