RED S and the Active Woman: When Under Fuelling Becomes a Performance Problem
- Seema Chopra
- Feb 3
- 4 min read
Updated: Feb 5
Relative Energy Deficiency in Sport, known as RED S, describes a physiological state where the body does not have enough available energy to support both daily function and training demands.
It was previously discussed as the female athlete triad, focused on disrupted menstruation, reduced bone density, and disordered eating. What RED S expands is the understanding that low energy availability affects multiple organ systems, and it can affect both women and men.
Most importantly, it is not confined to elite athletes.
What Is Low Energy Availability?
Energy availability is not simply calories in versus calories out.
It is the energy left over after exercise, to support essential functions such as:
hormone production
bone formation and repair
immune function
tissue recovery
mood and cognition
sleep regulation
When training, work stress, childcare, poor sleep, and dietary restriction overlap, the body may interpret this as scarcity and down regulate.
Sometimes this is deliberate restriction.
More often in athletic women, it is unintentional. They simply do not realise how much they need to eat.
Why It Shows Up in Dancers and Athletes
In younger dancers, the issue can emerge in environments with strong aesthetic and performance demands during critical growth periods.
In adult athletes, it can show up as long term under fuelling combined with a rigid relationship to exercise and food, sometimes paired with a lack of identity beyond training.
These are not failures of character. They are patterns that develop in cultures where pushing is rewarded and restoration is rarely taught.
Performance Impact: It Is Not Just About Health
RED S is often discussed as a medical problem, but it is also a performance limiter.
When energy availability is low, key hormonal pathways are suppressed. In women, oestrogen can drop significantly if periods stop, but the broader disruption can also include thyroid hormones, IGF 1 (important for muscle and bone adaptation), and stress hormone regulation.
This can lead to:
reduced strength profiles
blunted heart rate and blood pressure responses to exercise
reduced blood flow, particularly to the lower limbs
higher fatigue and slower recovery
flatter mood, reduced drive, and reduced willingness to push effort
increased injury risk, including bone stress injuries and other neuromuscular injuries
In simple terms, the body cannot adapt well when it does not have enough fuel to rebuild.
Injury Risk and Bone Health
Bone stress injuries are a common red flag.
Oestrogen, thyroid hormones, and IGF 1 support bone formation and reduce bone breakdown. When these hormones are disrupted, bone density can reduce over time, making the skeleton more vulnerable under impact and load.
This is particularly relevant for runners and dancers, but also for any woman doing high volume training while under fuelled.
RED S also affects muscle tendon units and neuromuscular control. Fatigue and reduced coordination can increase injury risk beyond bone.
The Pill and Why It Can Mask RED S
A common misconception is that the combined oral contraceptive pill protects against RED S.
It does not.
It can mask one of the key markers we often use, menstruation. If someone is on the combined pill, you lose the ability to use cycle changes as an early warning sign.
It also does not provide the same protective effect for bone health that many clinicians historically assumed. If RED S is suspected, clinical investigation is essential, and in some cases a clinician may discuss coming off the pill to assess true reproductive hormone status, alongside relevant blood tests.
What This Means for the Non Athlete
You do not need to be in professional sport to experience low energy availability.
If you are an active woman with:
high training load
high work or childcare load
poor sleep
chronic stress
restrictive dieting or food elimination
you can create the same scarcity signal in the body.
The answer is not fear. It is awareness.
A Practical Reframe for Training
Managing RED S is fundamentally behaviour change. Lectures rarely work. Fear rarely works.
What works is aligning change with personal goals.
If your goal is long term health, stable energy, balanced mood, and consistent training, then energy availability must support that goal.
Restorative practices are not optional extras. They are part of planning.
Dr Amal’s emphasis was on forward planning and controlling controllables:
eating enough, and knowing when you will eat
sleeping enough, and planning realistic training around life demands
building in deload weeks, avoiding monotonous high load programmes
beginning training early for events rather than ramping abruptly
respecting stress as a physiological variable that disrupts sleep and recovery
If you are unsure whether your body is coping, seek medical support early. Early education and early prevention matter.
If you want support building a balanced training programme that includes restoration, you can explore Active Shakti’s coaching approach.
Fuel is not a reward for training. It is what makes training possible.
Comments