Athletes are constantly pushing themselves to their limits, training rigorously to improve their performance and reach their goals; however, what many fail to realize is that no matter how hard they train, their diet plays a crucial role in their success.  With the right balance of nutrients, the body is able to efficiently convert food into energy, repair and build muscle tissue, and maintain overall health, allowing athletes to excel whether they are training for a marathon, lifting weights, or competing in a team sport.  When an athlete’s nutrition cannot keep up with the demands of their training, they can experience a syndrome known as Relative Energy Deficiency in Sport (RED-S) [1]. 

 

What is RED-S?

 

In the past, healthcare professionals used to diagnose a condition known as the “female athlete triad,” which consisted of low energy availability (LEA), menstrual irregularities, and low bone density [2].  This condition predominantly affected female athletes, particularly those in sports that emphasize a lean physique, such as gymnastics, figure skating, and distance running; as research and understanding of this condition have evolved, it has become apparent that it can also affect individuals of all genders in various sports and physical activities [2].

 

RED-S is a more inclusive and comprehensive diagnosis that acknowledges the complex interplay between energy availability, hormonal regulation, and bone health in athletes and active individuals while encompassing a broader range of symptoms including gastrointestinal issues, metabolic disturbances, compromised immunity, and impaired cardiovascular health [1,2].  It recognizes that a variety of factors, such as inadequate caloric intake, excessive exercise (especially combined with insufficient rest), psychological and physical stress, and genetic predisposition, can contribute to the development of these symptoms, which can have serious ramifications for an individual’s health and performance.

 

What Causes RED-S? 

 

RED-S occurs when an individual’s energy intake is insufficient to meet the demands of their physical activity levels, leading to hormonal imbalances and an array of negative health outcomes [1].  While the development of RED-S is multifaceted, one of the key contributing factors is the misconception that athletes need to maintain extremely low body weights in order to perform at their best [3].  This belief is perpetuated by societal pressures that prioritize a certain body type, often characterized by low body fat and high muscle definition. In sports that emphasize aesthetics or require athletes to meet certain weight categories, such as gymnastics, wrestling, or distance running, the pressure to maintain a lower body weight can be particularly intense [1].  As a result, many athletes, both male and female, may resort to drastic measures such as extreme dieting or excessive exercise to achieve this desired physique [1].  It is important to note that LEA in and of itself can be intentional, as in the case of anorexia nervosa, or unintentional, where an athlete’s diet simply cannot support their activity level.  While RED-S often co-occurs with eating disorders, it can also occur in the absence of an eating disorder, making it a distinct and separate condition [2]. 

 

Health Consequences

 

Unfortunately, this pursuit of a lean body composition can have detrimental effects on an athlete’s overall health and performance.  By restricting their calorie intake, regardless of intent, athletes are compromising their energy availability: the amount of energy left over after exercise to support essential bodily functions such as metabolism, growth, and repair [4].  When energy availability is chronically low relative to energy expenditure, the body adapts by downregulating key physiological processes in an effort to conserve energy [4].  This can result in a cascade of adverse health effects.   

 

The endocrine system, which regulates hormone production and release throughout the body, is one of the first affected by LEA.  In athletes with RED-S, hormonal imbalances can manifest as decreased estrogen causing menstrual abnormalities in females (aka amenorrhea), decreased testosterone resulting in sexual dysfunction levels in males, and alterations in thyroid function [4] (i.e., euthyroid sick syndrome).  These changes can have far-reaching consequences, affecting bone integrity, immune function, and heart health [5]. 

 

In addition to hormonal imbalances, LEA can also lead to psychological and emotional issues in athletes [4].  Chronic dieting and restrictive eating behaviors can contribute to feelings of guilt, anxiety, and stress, creating a negative cycle that can impact both mental and physical well-being.  Furthermore, all of this can detract from an athlete’s focus on training and performance, ultimately hindering their ability to reach their full potential.  

 

Other indicators of RED-S include fatigue, weight changes, overuse injuries, reduced recovery from activity, performance plateaus and/or decrements, and insomnia [5].

 

Preventing RED-S and Key Takeaways

 

It is crucial for athletes, coaches, and sports professionals to recognize the dangers of promoting extreme leanness as a performance-enhancing strategy.  Instead, the goal should be achieving a balanced and sustainable approach to nutrition and training that supports both health and athleticism.  This may involve working with a registered dietitian specializing in eating disorders to develop a fueling plan that meets the individual needs of each athlete.  Regularly monitoring energy intake, menstrual function (in females), bone health, and other physiological markers can help identify and promptly address RED-S to reduce the risk of long-term repercussions.

 

 

References

1. Farnsworth C. RED-S: Definition, symptoms, causes, treatments, and more. www.medicalnewstoday.com. Published January 4, 2024. Accessed July 24, 2024. https://www.medicalnewstoday.com/articles/red-s#affect-on-performance
2. Nickols R, ed. What is Relative Energy Deficiency in Sport (RED-S)? National Eating Disorders Association. Accessed July 23, 2024. https://www.nationaleatingdisorders.org/relative-energy-deficiency-in-sport-red-s/
3. Dooney E. RED-S: The Condition All Runners Need to Know About. Runner’s World. Published August 28, 2020. Accessed July 23, 2024. https://www.runnersworld.com/uk/health/a33589189/red-s-relative-energy-deficiency-running/
4. Cabre H, Moore S, Smith-Ryan A, Hackney A. Relative Energy Deficiency in Sport (RED-S): scientific, clinical, Andpractical Implications for the Female Athlete. Deutsche Zeitschrift für Sportmedizin/German Journal of Sports Medicine. 2022;73(7):225-234. doi:https://doi.org/10.5960/dzsm.2022.546 
5. RED-S in the Active Female. American Family Physician. 2022;106(1):60A60A. Accessed July 23, 2024. https://www.aafp.org/pubs/afp/issues/2022/0700/patient-information-red-s-active-female.html