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Relative Energy Deficiency in Sports | RED-S

Relative Energy Deficiency in Sports occurs in exercising people, where there is a mismatch between fuelling the body and energy availability to the body. 


RED-S is an important women's health issue in women who exercise or train regularly. In New Zealand approximately 45% of women who exercise recreationally are at risk of low energy availability, especially teens - because they have additional needs of growth, and those participating in weight-dependent and lean-sports.

We already lose many talented women from sport that under fuelling and lack of understanding of how training intersects with female physiology should not be one of the reasons women drop out of physical activity.


RED-S can be hard to detect especially for women taking oral contraceptives as the contraception masks the menstrual cycle function which acts as a marker of female hormonal and metabolic function.

Low energy availability (or LEA) is the driving force behind RED-S. It occurs when there is a mismatch exists between an athletes energy intake and the energy expended during exercise. 


When a female athlete isn’t consuming enough energy to match exertion, the body has a deficit in the energy it needs to support the body as a whole. An athlete may be able to exist in a state of low energy availability and relative energy deficiency for a season or two, but it is unsustainable over time, resulting in a decline in both short term performance and long term physical and mental health.

Symptoms of RED-S

  • Altered menstrual cycle - irregular cycles or skipped periods or delayed onset of periods in teens

  • Fatigue, low energy

  • Altered mood, poor concentration

  • Under-performance, failing to improve

  • Recurrent injuries

  • Loss of enjoyment from sport

  • Low mood

Health Consequences of RED-S

RED-S has important short and long-term health consequences including:

  • impaired bone health and strength and risk of stress fractures

  • irregular or absent periods

  • Inefficient energy metabolism

  • Lower infection resistance

  • Impaired protein synthesis - essential for muscle maintenance and body repairs

  • Cardiovascular health

  • Impacts psychological health including poorer resilience to stress.

Performance Consequences of RED-S

RED-S is also associated with poorer sports performance including:

  • Reduced muscle strength

  • Reduced endurance capacity

  • Increased risk of injury during training such as stress fractures, tendon and ligament injuries.

  • Slower recovery rates from both injuries and from training.

  • Impaired judgement and concentration

  • Reduced coordination

  • Anxiety and depression – as a direct consequence of RED-S, but also from pressures of under-performing, being ill or injured.

  • Irritability, decreased engagement in activity and sports, or burnout.


How can RED-S be prevented?

1. Consistent approach to fuelling across the day with regular meals, snacks and recovery options that are appropriate in nutrients and total energy (calories).

2. Recognising that training days across a week and training phases throughout a year can be significantly different with regard to energy requirements - and energy intake should be modified to reflect this

3. Avoiding prolonged periods without eating and optimising pre, during and post training or competition nutrition routines is vital to promote appropriate energy availability and reduce the risk of RED-S

4. Monitoring menstrual cycles, including ovulatory cycles and hormone levels as a vital sign of health.

How can athletes with RED-S be treated?

Many people and athletes with RED-S can be treated with the help of a qualified healthcare team. Treatment often involves increasing energy intake and/or decreasing the duration, intensity, or frequency of training sessions.


For some, overcoming RED-S can be achieved through sport nutrition and education. For others, treatment will require eating disorder recovery approaches.

We work with female athletes and those who train to monitor their health status using integrative medicine to holistically treat RED-S to ensure adequate fuelling for the work your body needs to do.


We educate and empower you to work with your menstrual cycles and fuel your body for optimal health so you can focus on training, competing and enjoying the sports you love. 

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