RED-S: Quietly Running on Empty

RED-S comes up a lot in my work. And not just in the therapy room. Sometimes it’s in the conversations I have with coaches, trainers, physios or nutritionists. Sometimes it comes up when I’m socialising with my sporty friends.

At times it’s mentioned confidently from a knowing of what it is. At other times it’s said less surely with a kind of question mark on the end and an implication that I need to fill in the gaps about this new thing that’s arisen.

The truth is that RED-S has been around for decades. It just used to be called the ‘female athlete triad’. The name change is necessary because we now know that it doesn’t just affect female athletes, and along with this new knowledge also comes a much greater understanding of how it affects athletes.

I’m so glad that it is picking up in awareness because, quite frankly, it’s something that I’ve been banging on about for years and I’m personally delighted to hear people talking about it.

First of all, though, what actually IS RED-S?

RED-S stands for Relative Energy Deficiency in Sport. In plain terms, it means the body isn't getting enough fuel to cover everything being asked of it — training, growth, hormones, immune function, mood, bone health, all of it. When there isn't enough energy coming in relative to what's going out, the body doesn't just quietly cope and get on with it. Instead it starts making decisions about what to prioritise and therefore what also to Deprioritise. It has to.

Often the first things to go are the ones you can't see: reproductive hormones, bone density, metabolic rate. The systems don't feel urgent day to day but they but matter enormously over time.

That's part of what makes RED-S so easy to miss, or to explain away. You can be running on empty for a long while before anything visibly forces you to stop.

What it can feel like

This is different for everyone, but some things come up again and again in the people I work with. A fatigue that doesn't lift with rest. Injuries — particularly stress fractures — that seem to happen more easily, or heal more slowly, than they should. Getting ill more often. Feeling cold a lot of the time. Digestive issues. Losing your period, or it becoming irregular, if you have one. Mood that feels flatter, or more anxious, or harder to regulate than usual. Sometimes a kind of mental fog — struggling to concentrate, or finding decisions that used to feel simple suddenly feel effortful.

And alongside the physical, there's often something else going on. A growing preoccupation with training and food that starts to take up more space than it used to. A fear of what might happen if you slow down. A sense that your worth is tangled up with your output — how hard you trained, how well you performed, whether you 'did enough' that day. That combination — physical depletion and a mind that's become increasingly focused on managing it — is a big part of what makes RED-S so hard to live with, and often even harder to leave behind.

Who's at risk, and why

RED-S can affect anyone in sport, at any level, but there are patterns.

Endurance athletes, those doing sports with weight categories or where aesthetics are judged tend to be more exposed. So for example, running, cycling, gymnastics, dance, rowing, some martial arts, swimming —

Others at risk are people going through periods of increased training load without a matching increase in fuelling, or those training through injury, growth spurts, or big life changes.

Part of why these sports carry more risk is cultural. In many of them, leanness isn't just noticed — it's praised, coached towards, and sometimes directly rewarded, whether through scoring criteria, selection, or simply the belief that lighter or leaner means faster, better, more likely to succeed. Over time that message stops feeling like an opinion and starts feeling like what’s needed to do the sport properly or what it means to be a performance athlete. When training is central to who you are, not just what you do then it becomes even harder to question.

On top of that, the practical maths often doesn't help either: high training volumes naturally demand more fuel, and in sports where there's pressure to stay lean, that increased need can end up in direct conflict with the pressure to eat less, or to eat in a very controlled way. It's a genuinely difficult bind to be in, and rarely one that's fully conscious.

The second group — those moving through increased load, injury, growth, or big life changes — tend to be at risk for a slightly different reason: energy needs shift, often quite quickly, and fuelling doesn't always shift with them. Growth spurts, for instance, demand a lot of energy that's easy to underestimate. Training through injury can mean the body's already working hard to repair itself while still being asked to perform. And big life changes — a new job, a house move, exams, a relationship ending — can quietly disrupt appetite, routine, and the headspace needed to eat well, even without any intention to under-fuel at all.

It's also worth saying that RED-S doesn't require an eating disorder to develop. It can happen through under-fuelling that's entirely unintentional — genuinely not realising how much energy a training load demands, or being so busy and so driven that eating properly slips down the list without any conscious restriction at all. That said, for some people, under-fuelling isn't accidental. And this is where RED-S and eating disorders can overlap, or sit very close to one another.

However, consistent underfuelling, for whatever reason, leads to psychological and behaviour changes around food, control and self-worth, that can become difficult to shift. More difficult than ‘just eat more’ or ‘you need to put weight on’.

It’s why it’s can be so hard for other people to understand – or even notice in the first place.

From the outside, you might look committed. Disciplined. Someone who trains hard and takes their sport seriously — which, in most contexts, gets praised. People don't tend to see the exhaustion that's become normal, the constant low hum of worry about missing a session, or the internal negotiating that happens around food and rest. They see the training log, the results, the drive. Not the cost.

Because RED-S sits at the intersection of the physical and the psychological, it can be genuinely hard to explain, even to people who care. How do you put into words that you're bone-tired but also can't stop, that you know something's wrong but the thought of eating more or training less brings up something closer to panic than relief? Coaches, teammates, family, even some healthcare professionals, can misread it as a fitness issue, a growth phase, or simply 'needing more recovery' — without seeing the emotional layer that's often driving the physical one.

That gap between what's actually happening and what's visible to others makes recovery harder, because so much of getting better relies on other people understanding what you need and why. If the people around you think this is purely physiological, the emotional part — the fear, the identity tied up in performance, the difficulty tolerating rest — can go completely unaddressed. And it's usually that part that keeps someone stuck.

Can I keep doing my sport, or do I need to step away to recover?

There isn't a single right answer to this. Sometimes recovery is possible while continuing to train and compete, with proper support and real changes to fuelling and load. Sometimes it isn't — not safely anyway, and not yet — and stepping back, even temporarily, is what's needed.

What makes this question so loaded, though, is identity. If you've spent years being 'the runner', 'the gymnast', 'the swimmer' — if sport has been where you've felt capable, or seen, or good enough — then the idea of stepping away doesn't just mean less training. It can feel like losing yourself. Who am I if I'm not doing this? It's a real question, and not one to brush past. I've sat with plenty of athletes for whom the fear of losing that identity was, quietly, a bigger barrier to recovery than anything physical.

I mean I’ve been there myself too! I spent a significant proportion of my athletic career in RED-S. I didn’t know that then and no one around me would have guessed. I blamed myself for my fatigue and believed that I either just needed to train harder, or get leaner – which one was most prominent on any given day depended on my results, who I was training or racing with and what was happening in the rest of my life. I did recover and part of that recovery involved deciding what sport meant to me and what I wanted from it.

This is often where counselling becomes useful — not to make the decision for you, but to help you get underneath it. To find out what your sport actually means to you, separate from performance and results. To build a sense of self that doesn't live or die by your training log. Sometimes that work makes space to return to sport in a healthier way. Sometimes it makes space to walk away, and find that you're still you on the other side. Either way, it tends to be a decision that goes better when it's made from a steadier place, rather than from fear.

Why counselling can help

RED-S is a physical diagnosis, but recovering from it is rarely only physical. Counselling can't change your bloods or your bone scan, but it can address a lot of what keeps someone caught in it.

That includes things like: the anxiety that shows up around rest and reduced training. The beliefs that link your worth to your output or your body. The difficulty trusting your body's signals after a long time overriding them. The grief that can come with stepping back from sport, or from the version of yourself that sport represented. And, where it's relevant, the relationship with food and control that RED-S can sit alongside, or sometimes obscure.

It also helps to have somewhere to be properly understood — where you don't have to justify how tired you are, or explain why 'just eat more and rest' isn't as simple as it sounds. That understanding, on its own, tends to make a real difference.

If any of this feels familiar, you don't have to have it all figured out before reaching out — whether that's what to call it, what caused it, or what you want to do about your sport. That's exactly what I’m here for.

If it would help to talk it through, I'd be glad to hear from you.