Low Energy Availability

Low energy availability means that the volume of energy available is not enough to adequately support all of the physiological functions and results in the body making metabolic shifts to preserve the most important functions that are needed to sustain life and, as such, suppresses other less essential functions to conserve fuel, like reproductive function. Thus, in exercising women, the amenorrhea is attributable to low energy availability where inadequate caloric intake combined with high energy expenditure causes an overall energy deficit. The energy deficit, in turn, stimulates compensatory metabolic shifts that cause weight loss and energy conservation, translating effects that result in hypothalamic suppression of ovarian function and amenorrhea. Mechanistically, when energy intake is inadequate to meet energetic demands, the body repartitions energy away from reproduction and growth and toward other more essential energy-consuming processes such as thermoregulation, cell...