Explaining RED-S and its impact on athlete health & performance

Posted on September 15, 2020 by

Not eating enough is not always something that is done intentionally.

Even with good intentions to eat well and thinking you are on the right track, a consistent large energy deficit can result in a misalignment of what energy is available to be used and what energy is required to be used to live and train.

This misalignment is termed Relative Energy Deficiency in sport (RED-S) and it has serious health and performance consequences if not addressed or goes unnoticed by athletes.


What is relative energy deficiency in sport (RED-S)?

The body needs energy for activities of daily life, training and bodily function like breathing, blood flow, maintaining healthy bones, muscles and hormones and keeping the heart beating. RED-S is a syndrome which shows up negatively in many of these essential body systems and occurs when your body does not have sufficient energy (calories/kilojoules) to maintain them adequately.

The food you eat each day gives you energy to fuel living and training. If you only eat enough to get you through training there will be less energy to expend on health. From here the body will start to shut down vital processes that assist with training recovery, re-fuelling, building muscle mass, immunity, growth, mood and for females a regular menstrual cycle.

It’s like spending all your money on a new pair of shoes and then having nothing left to buy a nice dress or suit; you either have to go on a strict budget or you go without!


How does RED-S occur in athletes?

This can eventuate over time but studies have show that merely three days of having low energy availability can start to impact upon these systems. Sometimes this might be happening without you even realising, that’s why its important to listen to the body to identify some signs if you are eating enough, and what happens when you don’t listen to those signs.

The circumstances where you can find energy mismatches occur when:

  • Food intake is reduced whilst training load remains the same: For example, you move out of home and this changes your habits, accidentally reducing food intake across the day.
  • Training load increases, but food intake remains the same: For example, your training sessions increase to twice a day but you continue to eat the same amount.
  • You are intentionally restricting food intake to less than what you were having: This may start as an attempt to lose weight or linked to disordered eating which is impacting food selection and has got out of hand.


What are the direct performance impacts of RED-S? 

Anything that impacts an athletes health will directly or indirectly impact performance, especially if it results in days of training missed.

The below diagram outlines how wide spread this impact can be:


How do I know if I have RED-S?

If you aren’t feeling as good as you think you should in and around training, or if you have a combination of the above factors or signs occurring you should speak to a dietitian to do a detailed assessment of your  dietary intake. To confirm RED-S however, usually a combination of blood tests to check hormones, bone scans or a resting metabolic rate test may also be required.

This is not one to self-diagnose, make sure you connect in with your performance team including the doctor to assess. And if you are unsure then always ask.


How long does it take to get out of RED-S?

This is very individual and depends on many factors, particularly how long you have had RED-S and training status. It can be weeks or months.


How do I prevent RED-S?

Listen to the body and stay aware of how you are adapting to training. Working with your dietitian they can advise a simple modification to the quantity of food, macronutrient intake or the timing of meals to suit your energy demands.

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