Have you been working hard but not seeing the results you had hoped for? Is your body aesthetic something that you consider often? Are you constantly fatigued? Are you losing weight? Are you on a calorie-deficient diet but training hard? Are you having irregular menstrual cycles? Do you think you have any disordered eating habits? Have you had one or more bone stress injuries? If you answered yes to any or all of these and are actively competing in a sporting environment, you may be suffering from Relative Energy Deficiency in Sport (RED-S).
RED-S is a fairly recent term that stemmed from “The Female Athlete Triad”, and occurs as a result of a sportsperson being calorie deficient (taking in less calories than they are exerting). Whilst this may seem like a significant pro for those that are training as a means of losing weight, it can have significant health implications for those that are low in weight/body mass index (BMI). Initially, a female athlete was deemed to be at risk of ill health/injury if they had eating disorders, amenorrhoea (the absence of a menstrual period) and decreased bone mineral density: the female triad. However, it has been appreciated that men can also be at risk and so the term RED-S was developed.
So what does RED-S mean? Simply put, RED-S is a result of insufficient caloric intake and/or excessive energy expenditure. The consequences can be significant, as RED-S can alter many physiological systems in including metabolism, menstrual function, bone health, immune system, protein synthesis, cardiovascular health and psychological health. If left unmanaged the recovery from deficits such as poor energy availability, inefficient menstrual status and bone health could take weeks, months and years respectively.
The classification of RED-S is a little unclear and is still being researched to provide more clarity. However, a recent Consensus Paper by the International Olympic Committee (IOC) provided a traffic light system for the diagnosis of RED-S. A red light would indicate that the individual should cease sport immediately and work to eradicate/reduce the the red light before partaking in a gradual return to sport. An amber light would indicate that the athlete should proceed to train with modifications and that further investigations would be warranted to reduce the relevant deficit. A green light would indicate no concern and that full training could continue.
Factors indicating a red light would include:
Anorexia nervosa and other serious eating disorders
Other serious medical (psychological and physiological) conditions related to low energy availability
Extreme weight loss techniques leading to dehydration induced haemodynamic instability and other life-threatening conditions - this could be seen within sports such as mixed martial arts where weight cutting over short periods of time is regularly performed.
Those that warrant further monitoring (amber light) would include:
Prolonged abnormally low percentage of body fat
Substantial weight loss (5–10% body mass in 1 month)
Attenuation of expected growth and development in adolescent athlete
Abnormal menstrual cycle: amenorrhoea >6 months
Menarche (onset of menstrual period) >16 years
Abnormal hormonal profile in men
History of 1 or more stress fractures associated with hormonal/menstrual dysfunction and/or low energy availability
Significant changes in eating habits
RED-S is most prevalent in sports with an emphasis on aesthetics or a lean physique such as ballet or long distance runners. The challenge in such environments is that the absence of regular menstrual cycles, altered eating habits and low percentages of body fat are highly prevalent. So, do we take all of these athletes away from their sport in order to make a point to the coaching staff and reinstate (what we believe to be) optimum health? Well, no.
The world of elite sport is a very complicated one. Were we to really put our foot down on the masses of these athletes, we would be sure to feel a significant backlash! From coaching staff who no longer have any athletes to compete, to the sponsors who no longer have their brand being flashed across the screens. The athletes themselves would also be bitterly unhappy with such a decision if it was not managed well. Diagnosis is complicated and there is no ‘one size fits all’ approach to classifying someone with RED-S. One athlete may have a diagnosed eating disorder but may maintain a healthy weight and function well with nil injury history. Should we take this athlete off training because he they have a ‘red light’? Probably not. Conversely another athlete may have a low, but stable, BMI with nil disordered eating habits but consistently breaks down with bone stress injuries and has low bone mineral density. No red flag, but probably at a greater risk than the athlete before them.
In summary, RED-S is a complicated black hole that requires significant discussion between a multidisciplinary health team before making a decision on future management. It can happen to both female and male athletes and lead to significant physiological changes, ill health and injury. Not only this, but a low-energy state (or under-fuelling) can lead to reduced performance capability. Early detection is paramount, and a high level of suspicion is warranted in endurance and lean body sports. Assessing for weight loss, recent training increases with ‘fuelling’ mismatch, lack of normal growth or development in adolescents, recurrent bony or soft tissue injuries, illnesses, decreased performance, mood changes and menstrual dysfunction are helpful signs. Treatment relies on a multidisciplinary approach to educate and support the athlete with the primary aim of correcting and maintaining energy balance.
Thanks for reading and feel free to leave your thoughts and opinions. I would also like to acknowledge a peer and friend of mine for helping with the writing of this blog post, Mr Wayne Kitchener. Cheers buddy.
Until next time
If you are interested in further reading, then have a look at the articles below:
De Souza MJ, et al. (2014) Misunderstanding the Female Athlete Triad: Refuting the IOC Consensus Statement on Relative Energy Deficiency in Sport (RED-S) Br J Sports Med 48:20: 1461-1465
Mountjoy M, et al. (2014) The IOC consensus statement: beyond the Female Athlete Triad - Relative Energy Deficiency in Sport (RED-S) Br J Sports Med 48:491-497
Mountjoy M, et al. (2015) The IOC relative energy deficiency in sport clinical assessment tool Br J Sports Med 0:1-4
Mountjoy M, et al. (2018) IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update Br J Sports Med 52:11:687-697
Marcason W (2016) Female Athlete Triad or Relative Energy Deficiency in Sport (RED-S): Is there a difference? J of the Academy of Nutrtion and Dietetics 116:4:744