Exercising women have a high prevalence of menstrual disturbances. In 2003, it was suggested that disruption in luteinizing hormone (LH) pulsatility occurs below a threshold of energy availability (EA) of 30 kcal/kg lean body mass (LBM)/day. This paper is a critical review of the evidence regarding the theory that disruptions to the reproductive axis and menstrual disturbances occur below the proposed threshold. Short-term laboratory studies demonstrated that 4-5 days of an EA below 30 kcal/kg LBM/day, induced with or without exercise, decreased serum triiodothyronine and LH pulse frequency, and increased LH pulse amplitude in sedentary, regularly menstruating women. Fewer studies have investigated downstream ovarian effects after long-term exposure to low EA. The Sargent Camp Study was the first randomized trial that induced luteal phase defects, delayed menses, and anovulation by causing weight loss (-4 ± 0.3 kg) with an abrupt increase in exercise volume for two menstrual cycles. The BioEnergetics Study was a randomized controlled trial that induced varying levels of energy deficits by manipulating energy intake and expenditure for three menstrual cycles. LH pulse frequency and triiodothyronine decreased, and 57% of women developed luteal phase defects, anovulation, and/or oligomenorrhea. An EA below 30 kcal/kg fat free mass/day increased the chance of experiencing a menstrual disturbance by 50%. However, menstrual disturbances were observed above and below that EA threshold, and changes in LH pulse frequency predicted only luteal phase defects, not oligomenorrhea or anovulation. The proposed EA threshold is not a cut-off below which menstrual disturbances occur, but represents an increased risk of experiencing menstrual disturbances.

Women\'s football is an intermittent sport characterized by frequent intense actions throughout the match. The high number of matches with limited recovery time played across a long competitive season underlines the importance of nutritional strategies to meet these large physical demands. In order to maximize sport performance and maintain good health, energy intake must be optimal. However, a considerable proportion of female elite football players does not have sufficient energy intake to match the energy expenditure, resulting in low energy availability that might have detrimental physiologic consequences and impair performance. Carbohydrates appear to be the primary fuel covering the total energy supply during match-play, and female elite football players should aim to consume sufficient carbohydrates to meet the requirements of their training program and to optimize the replenishment of muscle glycogen stores between training bouts and matches. However, several macro- and micronutrients are important for ensuring sufficient energy and nutrients for performance optimization and for overall health status in female elite football players. The inadequacy of macro-and micronutrients in the diet of these athletes may impair performance and training adaptations, and increase the risk of health disorders, compromising the player\'s professional career. In this topical review, we present knowledge and relevant nutritional recommendations for elite female football players for the benefit of sports nutritionists, dietitians, sports scientists, healthcare specialists, and applied researchers. We focus on dietary intake and cover the most pertinent topics in sports nutrition for the relevant physical demands in female elite football players as follows: energy intake, macronutrient and micronutrient requirements and optimal composition of the everyday diet, nutritional and hydration strategies to optimize performance and recovery, potential ergogenic effects of authorized relevant supplements, and future research considerations.

The syndrome of relative energy deficiency in sport (RED-S) is a clinical entity characterized by low energy availability, which can negatively affect the health and performance of both male and female athletes. The underlying mechanism of RED-S is an inadequacy of dietary energy to support optimal health and performance. This syndrome refers to impaired physiological function, including metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health, with psychological consequences that can either precede (through restrictive dietary habits) or result from RED-S. The term RED-S extends beyond the condition termed the \"Female Athlete Triad.\" Formerly known as synchronized swimming, artistic swimming is an Olympic sport requiring a high level of fitness as well as technical skill and artistry. The risk of RED-S is high in artistic swimming as it is an aesthetic, judged sport with an emphasis on a lean physique. RED-S is of significant concern in the sport of artistic swimming because of the potential negative effects on physical and mental health as well as consequences on athletic performance. This paper reviews health and performance consequences associated with low energy availability resulting in RED-S in artistic swimming. Medical and nutritional considerations specific to artistic swimming are reviewed, and methods to help detect and manage RED-S are discussed. Prevention and management of RED-S in this athlete population should be a priority for coaches, and the sport medicine professionals working with artistic swimming athletes should utilize the RED-S CAT, a Clinical Assessment Tool for screening and managing RED-S.