Relative energy deficiency in sports (RED-S)

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Relative energy deficiency in sports (RED-S) is a syndrome in athletes caused by consistently not getting enough fuel through food to support the demands of your daily physical activity and training. It is not an eating disorder but can put you at risk for developing, or can result in, one.

Key points

  • RED-S is a syndrome caused by consistently not getting enough fuel through food to support the demands of your daily physical activity and training.
  • Typical signs and symptoms include feeling tired and/or weak, significant weight loss, irregular/missed periods (for people who menstruate), trouble focusing, irritability, anxiety or depression, and frequent/increased injury and illness.
  • RED-S can affect athletes of any gender and ability level. You may be at higher risk of developing RED-S if you are a competitive athlete, your sport traditionally favours a thin or lean body type or requires frequent weigh-ins.
  • Over time, RED-S can lead to poor health and declining athletic performance.
  • You can help prevent RED-S by thinking of food as fuel, choosing activities that complement your natural body strengths, valuing health over competitive success, and being a body-positive role model.

What is RED-S?

Relative energy deficiency in sports (RED-S) is a syndrome caused by consistently not getting enough fuel through food to support the demands of your daily physical activity and training. You may be unaware of just how few calories you are taking in, or you may be limiting your food intake on purpose due to disordered eating or influence/pressure by a parent or coach. Over time, if you do not get enough fuel through food to support the energy demands of your daily training, RED-S can lead to poor health and declining athletic performance.

How is RED-S different from an eating disorder?

RED-S is a syndrome (a group of symptoms that happen at the same time) that occurs from not getting enough fuel through food to support the demands of your daily physical activity and training. It may overlap with disordered eating, be the result of disordered eating, or it can be a risk factor for developing an eating disorder.

What are the signs and symptoms of RED-S?

Physical

  • Feeling tired and/or weak
  • Quick and/or significant weight loss
  • Dehydration
  • Irregular/missed periods (amenorrhea) for people who menstruate
  • Frequent/increased injury (e.g., stress fractures, pulled muscles)
  • Slow injury healing
  • Heart problems (e.g., sudden drops in heart rate and/or blood pressure)
  • Delayed puberty
  • Having a low/decreased sex drive
  • Frequent illness (e.g., colds, flu)
  • Trouble staying warm
  • Hair loss
  • Digestion problems
  • Dental and gum problems

Psychological

  • Trouble focusing/concentrating
  • Irritability
  • Anxiety or depression
  • Disordered eating
  • Impaired judgment

Who is at risk for RED-S?

RED-S can affect athletes of any gender and ability level. However, you may be at higher risk of developing RED-S if your sport or activity traditionally favours a thin or lean body type (like ballet, figure skating, swimming, gymnastics, long distance running, cycling) or requires frequent weigh-ins (like boxing, wrestling and rowing). If you are a competitive athlete, you may also be at a higher risk compared to casual athletes.

How does RED-S affect my health and athletic performance?

Poor athletic performance

Many of the symptoms of RED-S can not only impact your overall health, but directly impact your performance as an athlete. This often happens in a ‘chain reaction’, with one symptom triggering the next. Feeling tired and having weak muscles can slow you down. It can also put more strain on your heart and lungs, which are working harder to keep up with your body’s pace. A lack of proper fuel through food can make you feel irritable and unable to focus, which can lead to poor performance, increased injury and slow healing.

Irregular/missed periods

For people who menstruate, exercising intensely and not eating enough calories can lead to a decrease in estrogen, the hormone that helps to regulate your menstrual cycle. As a result, your periods may become irregular or stop completely. When estrogen levels are low, you can experience delayed puberty and bone loss.

Brittle bones/low bone density

One of the more permanent effects of RED-S can be low bone density (brittle bones). When your body does not get enough fuel in the form of food, it can cause your bones to become weak and brittle. This is a risk to people of all genders, but especially to those who menstruate, and can lead to a permanent change to your bone health as your transition into adulthood. When your bones are weak, you are more prone to stress fractures, which can impact your ability to train and compete. These injuries will also be slower to heal and more likely to happen again over time.

How can RED-S be treated?

Treating RED-S can be tricky to do on your own. It can be helpful to seek out help from a broad support system like your doctor, a registered dietitian, a mental health counsellor, and your family, friends, and coaches. RED-S can be treated gradually by increasing your food intake to adequately support the level of your daily physical activity or by decreasing your daily exercise to accommodate your current diet.

It is possible to be admitted to the hospital for medical or psychological complications of RED-S, with or without an eating disorder, for not getting enough fuel through food to support the demands of your daily physical activity and training.

Depending on your signs and symptoms and level of risk, your doctor may recommend that you stop training. Practising self care and getting enough sleep will also help in recovery.

How can I prevent RED-S?

  • Think of food as fuel. Choose foods that are part of a healthy diet in quantities that are appropriate for your level of exercise, age, height, sex and body type. It can help to speak to a registered dietitian for personalized recommendations.
  • Choose activities that complement your natural body strengths and personal goals.
  • Look at the big picture. Your health is more important than competitive success and will have a greater impact on your life as you get older.
  • Remember that the thinnest/leanest/lightest athletes are not always the best in their sport.
  • Don't compare yourself to others. Your optimal weight, food intake and training routines will be unique to you and only you.
  • Be cautious of people who put your competitive success before your well being.
  • Be a role model. Practise positive eating habits, support others based on their talents and achievements, and shut down negative weight and body talk.
Last updated: June 10th 2022