The concept known as Relative Energy Deficiency in Sports, or RED-S, arises due to an athlete’s failure to take in sufficient energy to support daily exercise-related energy expenditure. The resulting low energy availability can promote various physiological/psychological dysfunctions, any of which can undermine sports performance. This article explores the causes of RED-S and highlights the signs and symptoms for which coaches and personal trainers might remain vigilant. We will also discuss the medical, social, and emotional ways to approach an athlete dealing with this condition to ensure optimal health and a quick return to sports.
Understanding Athletes’ Unique Energy Needs
Energy availability, a sports-related nutritional concept defined as the difference between daily energy intake via calories and energy expenditure, may seem like a basic math equation. However, in certain sports, meeting these energy demands can be quite problematic. Experts in this field have coined the term low energy availability, or LEA, to describe inadequate energy availability in a sports-athletic context. Whether an athlete suffers from chronic symptoms, often spanning weeks to several months, or an acutely severe situation (experienced as a mere few days of large energy deficits), LEA can lead to increased detrimental health outcomes. In 2014, the International Olympic Committee Medical Commission recognized what it calls the “Relative Energy Deficiency in Sport” syndrome.
We may recall the emergence of the so-called Female Athlete Triad syndrome from the early 1990’s, which described 3 symptoms frequently experienced by under-fueled female elite athletes: cessation of menstrual periods, decreased bone density and disordered eating behaviors. Over the last decade, the medical community came to recognize that this approach took too narrow a view on the problem. Hence, RED-S replaced the condition with a broader scope, seeing how these symptoms increasingly affected male athletes as well as female athletes, and also included many other symptoms that arise as a result of LEA.
Many athletes may fall prey to unintentional periods of LEA during intense training protocols, competitions, or in sports with high energy expenditure or involving weight restrictions. Most sports dietitians encourage such athletes to aim for consuming above 30 kcal/kg fat-free body mass/day, even if their workout/pre-competition prep protocols require them to lose body weight or body fat. Clinical studies have exhibited negative health implications in as little as five days of consuming <30 kcal/kg fat-free body mass/day.
The Low-Down on Low Energy Availability
If athletes continue to train and remain active in this compromised condition, they run the risk of altering their circulating levels of metabolic hormones and substrate utilization biomarkers such as insulin, cortisol, growth hormone, ghrelin, leptin, fatty acids, and ketones. In addition, athletes demonstrated lower blood glucose levels during fasted and post-exercise conditions, which typically points to an impaired ability to sustain glucose homeostasis. The diminished T3 levels will limit the ability of mitochondria to produce ATP from glycogen, which in turn slows the regeneration of phosphocreatine. The suppression of endogenous estrogen and progesterone can also negatively impact cardiovascular health, since estrogen has a direct impact on vascular function. Some studies have similarly demonstrated that irregularities in a female athlete’s menstrual cycle align with an increased risk for cardiovascular disease/increased arterial thickness.
Time off from sports and training as a result of injuries and illnesses related to LEA availability can quickly add up. Each week that an athlete must follow even a modified workout protocol can significantly reduce the chances of success at the elite level at which some athletes strive to compete. Missing workouts or having to modify them due to lack of available energy has emerged as one of the strongest predictors of sub-optimal performance at the highest level of sport; indeed, LEA served as a highly accurate predictor of illness among Olympic athletes prior to the 2016 Rio Olympic Games.
Signs and Symptoms of RED-S
Burning more calories than one consumes will, in a fairly short period of time, lead to perceptible symptoms and outwardly observable signs. Athletes often attribute these to other causes, as overlap with many conditions does exist. However, when taken together and in light of arduous exercise, the diagnosis of RED-S seems to surface. Below we list some of the general symptoms:
- Fatigue
- Needing longer rest periods between workouts
- Sleep difficulties
- Unintended weight loss
- Dizziness
- Dehydration
- Digestive disturbances such as gas, bloating, diarrhea and/or constipation
- Loss of hair
- Repeated stress fractures in the same area of the body
- Anxiety
- Depression
- Menstrual irregularities
Low energy availability proves quite difficult to diagnose and often gets overlooked, particularly since some symptoms remain less outwardly obvious than those listed above:
- Slowed heart rate
- Delayed puberty
- Loss of bone density
- Frequent illness/taking longer to recover from sickness
A vigilant personal trainer will often pick up on the following common manifestations of RED-S impairing athletic performance:
- Decreased muscle strength/endurance
- Impaired judgement/decreased ability to concentrate
- Increased risk of injury
- Decreased training response/coordination
Life After a Diagnosis
As vigilant as personal trainers and coaches try to remain, only a medical professional should have the final say on diagnosing RED-S. The diagnosis typically begins with a medical history, wherein the physician asks the athlete about symptoms such as weakness, fatigue, frequent colds, or an interrupted menstrual cycle. Inquiries should also include information regarding the athlete’s sport and training history: number of hours spent at the gym per week, whether training load has increased recently, and if the athlete has noticed a drop in performance. Blood pressure and heart rate will be assessed, and many clinicians also ask about the athlete’s eating habits/ food choices/attitudes toward food.
Based on the findings, the medical professional can determine whether the athlete is at high, moderate, or low risk for serious harm from RED-S. This, in turn, will help determine the athlete’s treatment plan, including which specialists should comprise the multidisciplinary team: sports medicine doctors, coaches, dietitians, sports psychologists, pediatricians, endocrinologists, etc.
Which Sports Pose a Higher Risk of RED-S?
While any elite athlete can at one point or another succumb to RED-S, certain sports seem to lend themselves to this particular condition. Sports that tie athletic success to a thin body can increase an athlete’s risk of RED-S. Coaches of figure skaters, gymnasts, and divers often emphasize ultra-slim body types and establish unrealistic goals. Sports with frequent weigh-ins, such as lightweight rowing and wrestling, increase the risk that athletes will severely cut back on calories to make weight. Endurance athletes also experience RED-S at higher rates than some other endeavors.
Changing the Face of Sports Culture
Regardless of the specific sport, the overall culture that surrounds a sports team can, in many ways, unwittingly contribute to RED-S. When coaches and teammates engage in “body shaming” or place too great an emphasis on winning over well-being, participants may feel pressured to both overexercise and under-fuel, ignoring signals from their bodies and pushing themselves to the very precipice of declining health.
When coaches and personal trainers take on the responsibility for a team of athletes, educating themselves first can foster a better understanding of what it takes to cultivate a healthy sports environment. Below, are some thoughts for coaches to consider:
- Teach athletes about healthy fueling habits – Encourage the team to avoid so-called “diet” foods and fads, prioritize a whole-food-first approach rather than relying on supplements, and fuel at regular intervals, including hydration.
- Remain confidential with personal data– If coaches deem weight monitoring a necessity, avoid public weigh-ins and treat data confidentially. Remain open and thoughtful regarding potential body image concerns or disordered eating history; conduct body composition tests infrequently and very selectively, if at all.
- Stress the importance of health over appearance, and maintain positive lines of communication.
- Have an awareness of warning signs – Athletes in any sport or of any body type can develop RED-S and/or disordered eating habits. Many individuals with RED-S/eating disorders do not present as visibly underweight. When working with young athletes, remember that bodies will change as these individuals grow and mature.
- Anticipate challenges and build a supportive network – Develop relationships with appropriate medical/psychological professionals to assist the team when necessary.
RED-S and Eating Disorders
If readers have begun to wonder how eating disorders and RED-S might intersect, the answer often gets clouded by the very minute details separating the two. Understanding and treating disordered eating, regardless of the cause, remains crucial, as many athletes with eating disorders may unknowingly restrict calories.
Within many sports, a culture of risk lurks beneath the surface, one that glorifies athletes who exhibit the ability to endure pain under any circumstances. This extreme behavior, often “re-branded” as a desire to win at all costs, sometimes leads to the false and dangerous belief that ignoring physical hunger represents fortitude and strength.
With a diagnosis of RED-S, athletes may not realize that their consumption falls short of their energy expenditure. An athlete could also consciously limit food intake, perhaps due to a misunderstanding of the energy required to excel in a particular sport. Sometimes offering a basic education about RED-S can motivate athletes to start fueling adequately.
For some athletes, consuming a less-than-adequate number of calories stems from a financial issue. College athletes, for example, may have placed themselves on a necessarily strict budget and therefore find it difficult to keep up with the energy demands of their training.
In the case of true eating disorders, under-fueling typically originates from distorted thoughts, emotions, challenges in one’s relationship to food, and/or a compulsive drive for thinness. When an athlete deals with anorexia or bulimia, other symptoms may appear in addition to those already mentioned, including fluid/electrolyte imbalances, dental problems, and tears in the esophagus.
Taking Steps Towards Recovery
If a coach has reason to suspect an athlete might suffer from anorexia or bulimia, they must understand their scope of practice and reach out to the appropriate specialists for proper care. However, guiding athletes towards recovery from RED-S can begin within the realm of coaching and training.
An ideal recovery process will involve a methodical and multidisciplinary approach. In this section, we will highlight the key aspects involved in setting the stage for a smooth transition from suspected or confirmed RED-S to a healthier approach and outlook for elite sports training and performance.
- Assess Energy Intake ~ The future success of an athlete’s performance hinges on making sure sufficient calories get consumed to match or exceed physical energy demands. Pre-workout and post-workout meals remain of utmost importance, with a keen eye on specific macronutrient requirements. By fueling every few hours with nutrient-dense whole-food snacks between meals as opposed to supplements, an athlete’s energy should remain consistent.
- Adjust Training Loads ~ If a coach or trainer notices a slip in progress, or if an athlete consistently falters during workouts, making necessary changes to training protocols—either lessening loads or reducing training volume/intensity—can help the body recover. This proves very difficult for some elite athletes who strive for perfection rather than excellence. In such cases, a sports dietitian can help set up a realistic recovery plan, including food and exercise.
- Incorporate Mandatory Rest Days ~ These serve as forced “down time”, which may at first frustrate athletes but will ultimately render them stronger and healthier. Teach athletes how to “listen” to their bodies and avoid unnecessarily pushing through fatigue.
- Monitor Progress/Hold Athletes Accountable ~ Regular check-ins with healthcare professionals can help RED-S sufferers track their recovery progress. Make sure the athletes understand the importance of allowing medical professionals to periodically assess bone density/hormone levels and, for female athletes, to monitor any missed menstrual periods.
Although RED-S occurs with increasing prevalence among elite athletes, it often gets overlooked when parents, coaches, and the athletes themselves fail to recognize the underlying factors. With “eyes on the prize,” sometimes taking too narrow a view can end up with an athlete suffering health issues and necessary recovery time from sports/training. Armed with the knowledge gained from this article, personal trainers should find themselves in an excellent position to guide their teams to a healthy and successful season!
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