In the world of sport, maintaining the delicate balance between energy intake and energy expenditure is crucial for optimal performance and overall health. When this balance tips towards a deficiency, it can lead to a condition known as Relative Energy Deficiency in Sport (RED-S). Originally conceptualised as the Female Athlete Triad, the understanding of energy deficiency has since evolved to include a broader spectrum of symptoms and affect both male and female athletes. Let's delve into what RED-S is, its origins, and the importance of maintaining adequate energy availability.
The Female Athlete Triad, first described in the early 1990s, focused on three interrelated health issues in female athletes: disordered eating/energy deficiency, menstrual dysfunction, and decreased bone mineral density. This triad highlighted the specific risks to female athletes but did not account for similar issues in male athletes or the broader range of physiological and psychological consequences of energy deficiency. Recognising these limitations, the International Olympic Committee (IOC) introduced the concept of RED-S in 2014. This expanded framework acknowledges that both male and female athletes can suffer from energy deficiency and includes a wider array of health impacts. RED-S affects metabolic rate, immune function, protein synthesis, cardiovascular health, and gastrointestinal function, among others. It also highlights the negative impact on athletic performance, including reduced endurance, strength, coordination, and increased injury risk.
At the heart of RED-S is the concept of energy availability (EA). EA is defined as the amount of dietary energy remaining for the body's physiological functions after accounting for the energy expended in exercise. It is expressed in kilocalories per kilogram of fat-free mass (FFM) per day (kcal/kg FFM/day). The accepted thresholds for EA are as follows:
Low energy availability can have widespread effects on an athlete's health and performance:
Diagnosing RED-S involves a comprehensive evaluation, including dietary assessments, physical examinations, and potentially laboratory tests to check for hormonal imbalances and other health markers. Given the broad impact of RED-S, a multidisciplinary approach is often necessary, involving dietitians, physicians, psychologists, and other healthcare professionals. Management focuses on restoring energy balance through dietary changes, reducing exercise intensity or volume, and addressing any psychological issues. Education on proper nutrition and the importance of maintaining energy balance is crucial for prevention.
The shift from the Female Athlete Triad to RED-S marks a significant advancement in understanding the full impact of energy deficiency on athletes. By recognising the broader range of affected systems and including both sexes, RED-S provides a more holistic approach to the health and performance of athletes. Maintaining optimal energy availability is essential not just for peak athletic performance but also for long-term health and well-being.