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RED-S: The condition all runners need to know about

In a culture that promotes a ‘no excuses’ attitude towards working out, pushing yourself beyond your limits is often celebrated as a sign of discipline, grit and physical strength. If you want to run faster, say those who proclaim themselves as experts on social media, you need to run more – push harder, show no weakness.

But as we fixate on improving our performance and reaching new goals, we rarely consider the future losses that may be the result of our present gains.

An unhealthy endurance athlete may seem like a paradox, but it’s a lot more common than you may think. And RED-S is a syndrome that affects countless sports fanatics – many of whom don’t even know it exists.

What is RED-S?

RED-S refers to Relative Energy Deficiency in Sport. Previously called the Female Athlete Triad, it is characterised – as you’d expect from the name – by low energy availability due to a long term/ ongoing calorie deficit.

RED-S as a term was coined by the International Olympic Committee back in 2014 – and because of that, you’d be forgiven for thinking it only affects elite athletes. But it can in fact affect anyone – male, female, elite or amateur. And it can lead to irreparable damage, impairing almost every system in the body if left untreated.

However, as RED-S remains little known in the general medical and athletic community, it often goes overlooked. And so it exists under the radar, often only drawing attention after a drastic injury or mental collapse.

‘It is still a relatively new condition,’ explains Sports and Eating disorder specialist dietitian, Renee McGregor. ‘It is a clinical condition within a sporting community, so only practitioners trained in both clinical and sports science/medicine will have a full understanding of it.’

However, as the evidence of its dangers mount, more people are speaking out to raise awareness about the syndrome. One of these voices belongs to Team GB runner Pippa Woolven, who suffered from the debilitating condition for over five years. Woolven’s full-time job is now focused on improving awareness, prevention and recovery outcomes among sports and medical communities. Her recently established organisation, Project RED-S, provides a web platform signposting athletes to the right medical, nutritional and psychological support.

Here, she shares her own experience with RED-S with Runner’s World and tell us more about the project…

Warning signs of RED-S

RED-S manifests in a variety of physical and psychological symptoms, many of which unfortunately often go unnoticed, at least initially. It might start with a series of benign colds and general fatigue, and so it’s unlikely to sound any alarm bells at first.

‘It was worryingly easy to dismiss the initial warning signs, since they were all relatively subtle in isolation,’ Woolven says.

But these seemingly minor symptoms are in fact indicative of the body slowly breaking down. ‘Biological processes become depressed,’ McGregor explains. ‘When there is not enough energy in the system, digestion slows, resulting in bloating, discomfort and IBS symptoms.’

Stubborn sniffles and chronic coughs are another side effect of this deficit. ‘The immune system also becomes impacted, which puts the individual at a higher risk of infections and illness’ explains McGregor.

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One of the key symptom of RED-S in female runners is hypothalamic amenorrhea, or the absence of menstruation. While regular periods are a sign of good health, they can also be a major hindrance for many female athletes. The problem can be that their disappearance – however unhealthy – is often a welcome relief from monthly cramps, headaches and mood swings, all of which can also impact training and racing.

‘It seemed more convenient not to have them,’ Woolven reveals. ‘I didn’t have to worry about being on my period during competitions or buying tampons anymore.’

This acceptance of amenorrhea speaks to an uncomfortable truth about RED-S – that it’s early symptoms can perversely actually enhance performance – in the short-term. Excessive training and restrictive eating leads to lower body weight, which can result in faster times – again, in the short term. And so the detriment of these behaviours is obscured by their immediate benefits – more PB’s, more medals and more acclaim on social media. This can reinforce the problem.

‘In my mind, I was just doing what it took to reach my potential in sport. I thought the odd illness, body image issue and low iron levels were just part of the challenge,’ Woolven says.

The danger of RED-S therefore lies not just in its symptoms, but in our failure to recognise them as symptoms.

RED-S is not an invisible illness that wreaks havoc on our internal organs as we ignorantly carry on with our lives: it waves at us in a bunting of red flags, but we remain colourblind to its warnings. In a society warped by messages like ‘No pain, no gain’ and ‘Eat less, move more’, it’s easy to view physical hardship as fundamental to making progress.

Our ability to detect health problems can, ironically, be corrupted by our determination to reach our fitness goals.

The responsibility of others

With athletes often unable to identify the issue objectively, it’s therefore crucial that their support team develops an understanding of RED-S.

Unfortunately, the initial ‘pros’ of the condition are often applauded by coaches for the same reasons as the athletes themselves – because of the short term positive results it may bring. Many doctors also have little knowledge of the condition, which further delays diagnosis. Despite displaying all the symptoms, it took years for Woolven to discover she had RED-S.

‘I’d had countless blood tests, seen multiple doctors and endocrinologists and not once was RED-S or the Female Athlete Triad suggested’ she explains.

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Woolven also emphasises the importance of discussing menstruation more openly in the athletic community. A loss of periods, which is a major indicator of RED-S, is often normalised in female runners, and can therefore go unnoticed.

‘Every doctor who looked at my body weight and food consumption reassured me: no period – no problem,’ Woolven reveals.

The female body requires a certain amount of energy to make sure reproductive hormones regulate and produce a monthly period. Hormones such as oestrogen are also crucial for bone health, cardiovascular health and cognitive health.

‘During amenorrhoea, when these hormones are reduced and often non-existent, individuals put their health and performance at risk,’ explains McGregor.

The diagnosis

Exhausted from her futile chase of a concrete diagnosis, Woolven finally decided to take matters into her own hands. She came across a series of articles and blogs on RED-S, and was shocked to discover how accurately they detailed her own symptoms.

Despite the relief of finding an answer after years of confusion, Woolven felt frustrated by the vagueness of the condition. ‘At first, I couldn’t believe that the simplicity of the RED-S description could possibly explain the complicated nature of my problem.’

As she delved further into her research, Woolven was confronted by a painful realisation – her body had been undernourished for years.

‘It became apparent I had quite simply spent years in an energy deficit that was far from replenished during the “reset” I thought was behind me,’ she admits.

This prolonged energy deficit is far from benign. The long-term consequences of RED-S include, but are not limited to, decreased bone density, cardiovascular issues, gastrointestinal disturbances and decreased immunity. Armed with this new information, Woolven embarked on a plan to salvage her deteriorating health.


With RED-S often taking years to be diagnosed, there is no fast lane to recovery. As many of its physical symptoms actually stem from a mindset that can be deeply entrenched, effective treatment requires a focus on mental health, as well as physical. Initially, Woolven attempted to loosen her rigid attitude towards nutrition and training on her own.

But despite her good intentions, the process was a lot harder than she had expected. ‘I seemed to be stuck in an agonising middle ground; motivated enough to start the process but continually falling short, time and time again,’ she says.

After ‘a series of half-hearted efforts and frustrating partial comebacks’, Woolven took a crucial step in her recovery – seeking professional guidance. With the help of a psychotherapist, she dug deeper into her disordered eating patterns and established a plan to combat these unhealthy behaviours.

Woolven also began to take time away from running, to pursue other hobbies and invest time in close relationships. To her surprise, varying her interests only benefited her training. She quickly realised that she did not have to neglect all other aspects of her life to reach her athletic goals.

‘Ironically, I performed at my worst when I was overly focused on sport,’ she explains.

Project RED-S

Woolven’s experience inspired her to establish Project RED-S – the go-to RED-S resource, where athletes – both amateur and professional – can learn about the condition and find access to the right support.

When Woolven first started to blog about her experiences and her recovery from RED-S during the first Covid-19 lockdown, she was shocked by the number of people who reached out to her asking her for help. It was at this point she realised the growing need to not only create an online resource on RED-S but also a community for those affected.

Right now, Woolven is offering one-to-one mentorship for affected athletes via the website, but is also in the process of building a community platform where athletes can provide each other with peer-to-peer support. ‘The people who can help you on your journey extends so far beyond a medical doctor or a dietician, because even when you know, “I need to eat more and do less”, it’s not always easy for people who have been conditioned to believe that’s the path to success.’

Woolven began creating the website independently alongside her full-time job with the National Trust two years ago, but after securing some financial backing last year from a parent of an athlete who had been through a similar experience to herself, has now been able to leave her job to focus solely on the project.

‘It’s been a whirlwind,’ she says. ‘Since then, I’ve been making connections and raising awareness by building a team of ambassadors and advisors, populating the website, and delivering presentations. This is a seriously common problem, yet there’s an overwhelming lack of knowledge and understanding about it.

‘We want every athlete, coach and other member of their support team to know what RED-S is, how to avoid it, and how to recover if they’re already struggling. We’ll be looking to some financial sponsors for some long-term support because at the moment, I’m just a one-woman band and we need money to grow this – to create awareness campaigns, educational courses and fund more research.’

Right now, one of Woolven’s main goals for the organisation is to provide athletes, who believe they may be experiencing symptoms, access to a trusted database of experts. ‘So many nutritionists and GPs aren’t clued up on this. As is the case for a lot of female runners, a number of doctors and even endocrinologists actually encouraged me to go on the contraceptive pill – there’s been some badly misinformed research out there that suggests the contraceptive pill protects your bone density, which is based on inconclusive science and isn’t supported by any substantial evidence. This is a common misconception and sadly, leads to many women masking the issue of irregular missing menstrual cycles.

‘The sooner you can get help from the right resources, the sooner you’re more likely to recover, and the more chance you have of turning it around without it reaching an extreme.’

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