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What you need to know about RED-S

by Stephanie Jamain 15 Aug 2023
What you need to know about RED-S

Relative Energy Deficiency in Sport (RED-S) was previously known as the “female athlete triad” or “athlete triad”. RED-S is caused by low energy availability, which essentially means that the energy or calories available do not meet the demands of the body. The athlete triad was characterized by disordered eating, stress fractures or decreased bone mineral density and absent or irregular menstrual cycles. There is some debate among experts about the name change from athlete triad to RED-S. . It’s important to understand that RED-S can exist in both elite and professional athletes as well as recreational athletes and what makes an individual at-risk of RED-S.


Low energy availability can happen from intentional calorie restriction such as disordered eating or eating disorders or it can be unintentional, such as high volume of training with insufficient caloric intake. When the demands of exercise combined with the demands of vital life processes exceed the amount of fuel available, something has to give. The body starts to shut down some of the processes that aren’t absolutely necessary for survival to conserve energy for other functions. This means ovulation can be altered in women and testosterone production can be impacted in men. 


Low energy availability also impacts bone mineral density, injury risk and risk of illness. Athletes that suffer from recurrent illnesses or injuries may be at-risk for RED-S. It’s important to understand that RED-S exists on a spectrum, the more severe the energy deficiency the more severe symptoms will be present. Recurrent injuries, slightly irregular cycles and low energy availability left unidentified and untreated can lead to bone stress fractures, lack of menstrual cycle (with no other apparent cause) and disordered eating or an eating disorder. While the hormone disruption that occurs in men is less clear than irregular menstrual cycles, RED-S can still exist in male athletes. Symptoms of low-testosterone including persistent fatigue may be associated with RED-S. 


Athletes that may be at a higher risk for RED-S include: 

  • Endurance athletes that have a high volume of training, and it’s often difficult to take in enough calories to meet energy demands; 
  • Aesthetic sport athletes such as artistic swimmers, figure skaters and dancers that may experience pressure of obtaining a certain physique considered typical or ideal in their sport, increasing the risk of disordered eating or caloric restriction; 
  • Weight class athletes, who often have to ‘make weight’ through caloric restriction at different times in their season.  

Performance suffers in underfuelled athletes and long-term health can be impaired as a consequence of RED-S. Athletes with a history of RED-S have a higher risk of osteoporosis later in life. Ongoing evaluation of individual athlete nutrition and training volume can help prevent the development of RED-S. If you think you may be somewhere on the spectrum of RED-S, speak to a qualified sports dietitian or clinician who can help you identify your risk level using the RED-S-CAT (Clinical Assessment Tool), linked here, to manage your risk of RED-S and improve your health and performance! 


Dr. Briana Botsford

Naturopathic Doctor & BRAVA Ambassador

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