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Relative Energy Deficiency in Sport (RED-S): Beyond the Female Triad

Has this patient presented to your office? She competes in collegiate cross country and has a concern of a recalcitrant ankle sprain. She has earned personal records three times this year. She is thin but not emaciated. She seems eager to return to her sport. She throws herself into physical therapy, wears the prescribed brace, and rests as advised.

Nonetheless, she does not heal. She briefly mentions not having a menstrual cycle since she was 17 years old. A mention of possible full immobilization causes her face to crumple. She laments that her coach will be so upset and her parents disappointed.

Does this next patient sound familiar? He is a wrestler with a stress fracture that will not heal. He is county champion in his weight class, muscular, without much body fat, but wears sweats when the temperature outside reads 90 degrees Fahrenheit. A scholarship awaits him in the fall. He mentions having trouble concentrating in his classes but chalks it up to extra training.

Both of the above scenarios should be on your radar for RED-S or relative energy deficiency in sport. While more studied in females (it used to be known as the female athlete triad) because of the monthly tracking availability in the menstrual cycle, it is also just as dangerous in male and non-binary athletes.1

What is RED-S?

Relative energy deficiency in sport, or RED-S, is impaired physiological function caused by relative energy deficiency.1 The International Olympic Committee renamed the female athlete triad in 2014 when they developed a consensus statement outlining whom this condition affects and how. Since then, much research devoted to this syndrome reveals that it affects not only menstruation and bone health, but many other physiological functions as well.1 The importance of recognizing this syndrome in female, male, and non-binary athletes is crucial, as sometimes the first practitioner the athletes will see is a podiatrist. One study of physical therapists, who may come into contact with the athletes even more, revealed that they may either not recognize RED-S, or assume someone else will take care of it.2

Who is at Risk for RED-S?

The etiology definition of RED-S is one of low energy availability. In other words, this condition exists when one’s diet does not effectively support the body’s function to maintain optimal health and performance.3 The energy expended in exercise exacerbates this deficit. Unfortunately, although RED-S is difficult to detect, one often finds it in sports where there are weigh-ins or where there is a pressure to be thin due to performance or score.3 It can be hard to detect or inquire about in an athlete, as many menstruating athletes think that having an irregular period, a

The above represents a list of potential symptoms and manifestations of RED-S as defined by the International Olympic Committee in their consensus statement of 2018.1 The challenge for clinicians is that these symptoms can appear for many other reasons. Photo courtesy of Doug Richie, DPM.

sign of low energy availability, is normal.3

At first, the weight loss associated with early low energy availability with or without an eating disorder may actually improve performance in sports like endurance running and cross country. The misconception about loss of menses and other decreases in function can often be systemic within a sport, with coaches pushing the antiquated ideas of the gladiator mentality. This is the concept by which one believes that training harder and harder will yield results, and, if one is not achieving those results, it is because they are not training hard enough. This is very hard to fight, and often patients do not realize they have a problem. The difficulty with treating or even identifying RED-S is that it can look like many things. But, early detection is critical to prevent long-term health sequelae.4 It may present as a non-healing injury or a patient with continual injuries despite taking adequate rest time.

Pertinent Signs and Symptoms That You Should Know

All of the following symptoms or potential performance consequences can be a sign of RED-S as defined by the International Olympic Committee in their 2018 paper:1

• Increased injury risk

• Decreased coordination

• Decreased concentration

• Irritability

• Depression

• Decreased glycogen stores

• Decreased endurance performance

• Decreased muscle strength

• Decreased training response

• Impaired judgment

RED-S affects so many systems that it may take one’s best detective skills to tease out the information. It could be that the patient mentions that there is a cold they cannot get past (immunological dysfunction), it could be they are on medication for anxiety or depression. It may present as thyroid symptoms, or perhaps you notice the patient mentions they have to take antacids several times a week (due to gastrointestinal issues). Most young people will explain this away and maybe even relate all the problems to stress, but it is up to you as the clinician to realize that this can all be due to low energy availability. It is important to note that while physique athletes (body building, etc) may not have the body habitus one might expect from disordered eating, they are especially at risk due to the normalization of disordered eating in their sports.5

The following bodily systems can all be affected by RED-S:1

• immunological

• reproductive (menstrual function)

• musculoskeletal (bone health)

• endocrine

• metabolic

• hematological

• growth and development

• psychological

• cardiovascular

• gastrointestinal

How Podiatrists Can Help Patients Dealing With RED-S

It is important to speak with your patients frankly about all of the health consequences related to low energy availability and RED-S. Sometimes it is a relief for the patient to find out that many other things going on with their body may be related to this lack of energy. The uphill battle entails grappling with their mindset about getting help, possibly an exercise addiction, and their perceived external pressures (whether present or not).6

Recovery often requires a multi-disciplinary team and willingness on the part of the patient. This buy-in can prove difficult, as athletes often have outside pressures depending on the point in their season and the expectation of coaches or teammates.7 Recommendations include having a general practitioner, psychotherapist, exercise physiologist, and dietitian on the same team. A great treatment contract is available from the IOC, as well as the REDS CAT screening tool.7

Determining Safe Return-to-Play Parameters for Athletes With RED-S

The IOC recommends screening a patient for risk level when determining when to return to play: 7

Low risk or “green light” is when the patient can return to sport safely. This entails appropriate physique managed without undue stress or dieting.

The IOC recommends screening a patient for risk level when determining when to return to play: 7

Low risk or “green light” is when the patient can return to sport safely. This entails appropriate physique managed without undue stress or dieting.

“Yellow light” or moderate risk patients may train as long as they follow a treatment plan. A “yellow light” patient may present as someone who has not reached menarche by age 15, or with an irregular menstrual cycle, someone with reduced bone mineral density, or a patient with psychological complications due to disordered eating, etc.

“Red light” or high risk status results in recommendations for no competition and no training. The IOC recommends a use of a written contract at this point. These situations may include anorexia nervosa, severe ECG abnormalities like bradycardia, or use of extreme weight loss techniques leading to dehydration (prevalent in weigh-in sports like wrestling and lightweight crew).

Final Thoughts

These athletes need an advocate in their corner, someone in a position of authority, even if or when they fight you every step of the way. The issue is that RED-S results can affect these athletes for the rest of their lives. I urge you to have a difficult conversation when the need arises.6 The references cited in this piece provide excellent information for patients and providers. If you treat an athlete whom you think may suffer from RED-S, a relatable resource is the blog of Anna Boniface, a British physiotherapist, and former British Marathoner. She documents her struggle with RED-S as an athlete and as a practitioner on her site: .

Dr. Piselli practices in Southampton, NY. She is a Diplomate of the American Board of Podiatric Medicine. She is a former starter and captain for Stanford Women’s Lacrosse Team. She is First Vice President of the American Association for Women Podiatrists.

This content was created in partnership with the American Association for Women Podiatrists.

1. Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52:687-697. doi: 10.1136/bjsports-2018-099193.

2. Gillbanks L, Mountjoy M, Filbay SR. Insufficient knowledge and inapproriate physiotherapy management of relative energy deficiency in sport (RED-S) in lightweight rowers. Phys Ther Sport. 2021;54:8-15. doi: 10.1016/j.ptsp.2021.12.002.

3. Lodge MT, Ackerman KE, Garay J. Knowledge of triad and RED-S in female cross-country athletes and support staff. J Athl Train. 2021. Online ahead of print. doi: 10.4085/1062-6050-0175.21.

4. Boutari C, Pappas P, Mintziori G, et al. The effect of underweight on female and male reproduction. Metabolism. 2020;107:154229. doi: 10.1016/j.metabol.2020.154229.

5. Whitehead J, Slater G, Wright H, Martin L, O’Connor H, Mitchell L. Disordered eating behaviours in female physique athletes. Eur J Sports Sci. 2020;20(9):1206-1214. doi: 10.1080/17461391.2019.1698659.

6. Mountjoy M. #Time2Act: Harassment and abuse in elite youth sport culture. Br J Sports Med. 2020;54:367e368. doi: 10.1136/bjsports-2020-101975.

7. Mountjoy M, Sundgot-Borgen J, Burke L, et al. The IOC relative energy deficiency in sport clinical assessment tool (RED-S CAT). Br J Sports Med. 2015;49(21):1354.

Additional References

8. Papageorgiou M, Dolan E, Elliott-Sale KJ, Sale C. Reduced energy availability: Implications for bone health in physically active populations. Eur J Nutr. 2018;57(3):847-859. doi: 10.1007/s00394-017-1498-8.

9. Reinking MF, Alexander LE. Prevalence of disordered-eating behaviours in undergraduate female collegiate athletes and nonathletes. J Athlet Train. 2005;40(1):47-51.

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