The Problem

This page starts with some definitions surrounding RED-S. You can get a grasp of the signs and how to spot them here, read more about the consequences here, and explore what you can do about it here. But first...

What exactly is RED-S?

RED-S stands for Relative Energy Deficiency in Sport. The condition is exactly what its name implies: a shortage of energy available to keep up with the demands of exercise, on top of essential daily functions (e.g. growth, respiration and digestion). The term ‘low energy availability’ is used to describe the negative balance – intentional or unintentional – between energy intake (i.e. food consumed) and energy expenditure (i.e. physical exertion). Over a period of time, this can result in RED-S.

RED-S can affect any athlete, of any age, gender or level, size or weight and has serious long-term health and performance implications. In the face of low energy availability, the body goes into 'energy saving mode' which negatively affects almost every system in the body – including essential functions such as the repair of muscle tissue, the reformation of bone, and the production of hormones, to name just a few. Among females, one concerning effect of RED-S is suppression of the female reproductive system, which can result in menstrual disturbance and Hypothalamic Amenorrhea (HA).

While the basic concept of RED-S as an energy imbalance is relatively simple one, prevention, identification and treatment of this common and serious condition is poor. The symptoms of RED-S often overlap with those of its precursory condition, the 'Female Athlete Triad', which as the name suggests, focused only on females and comprised of three inter-related parts: insufficient energy intake, amenorrhea and decreased bone density. As research evolved, low energy availability was found to not only impact males as well as females, but individuals who don’t necessarily define themselves as ‘athletes’ too. And, whilst menstrual function and bone health are often both impacted by low energy availability, the consequences extend to a far wider range of physiological and psychological components across all genders. So, in 2014, the International Olympic Committee introduced RED-S as a more inclusive term to describe the far broader range of individuals impacted by these multidimensional consequences.

Hypothalamic Amenorrhea

‘Amenorrhea’ is the term used to describe the loss of a menstrual cycle. It is a common consequence of RED-S, since when the body enters into 'energy saving mode', resources are directed away from less essential bodily systems for survival. The hypothalamus is the area of the brain responsible for regulating the hormones involved in this process, hence the name 'hypothalamic amenorrhea' (HA).

Medically speaking, there are two forms of amenorrhea:

Primary amenorrhea = when a girl’s menstrual cycle hasn’t started by age 15

Secondary amenorrhea = the absence of menstrual periods for 3 consecutive cycles in a female with previously regular cycles or 6 months for someone with previously irregular cycles

In either scenario, amenorrhea should be taken seriously. Worryingly, missing periods are often normalised within sport settings. Many athletes, coaches, parents and even doctors seem to miss the crucial link between amenorrhea and an energy deficit. Yet more worryingly, doctors are even likely to encourage use of the Contraceptive Pill, rather then investigate the underlying cause.

Take note: The bleed you experience on the Pill is a withdrawal bleed, as opposed to a natural period produced by a healthy menstrual cycle. The pill is absolutely not a suitable substitute for a natural menstrual cycle, no matter who has given you this idea in the past. More on this here.

Please also note HA is not a prerequisite for RED-S. Some females (and obviously all males) experience RED-S without losing their period.

Finally, there are a few underlying health conditions, besides RED-S, that can cause amenorrhea, so it’s important to rule these out with a medical professional before trying to tackle it alone. Find some tips on how to get the most out of your appointment here.

Who’s at risk of RED-S?

Athletes whose training demands significant energy output (e.g. endurance sports) and those whose activity promotes a low body weight (e.g. for aesthetics or performance) tend to be at the greatest risk for developing RED-S. There are two reasons for this. Firstly, endurance sports, by nature, demand a lot of energy – which can be underestimated by athletes who simply don't realise how much nutrition is needed to support these demands. Secondly, where there are pressures to look a certain way or be a certain weight, athletes are more likely to restrict their food intake or focus on a particular diet in order to gain a perceived performance advantage.

Certain sports (such as long distance running, climbing, gymnastics, rowing and cycling) involve both a high training load and pressure regarding body composition, making athletes competing in these sports most susceptible to RED-S. However, with the endless bombardment of fad diets, social media influences and ‘health’ bloggers promoting the need to look, exercise or eat a certain way, almost anyone can be at risk.

How do I know if I have RED-S?

RED-S is a clinical condition, diagnosed by blood tests and a full assessment of an athlete's relationship with training and nutrition. Whilst every individual is unique, there are a number of common symptoms that can be identified without medical help.

As I explained here, many of these symptoms are subtle and therefore easy to ignore. It is essential to be honest when assessing your relationship with training and nutrition. Even if your current routines and diet seem to be sustaining you through your training, dismissing the symptoms of RED-S can be extremely damaging in the longer-term.

Other methods of assessing your RED-S condition will involve blood testing for various hormone levels (for more information, head to: Talking To Your Doctor.) and bone density testing via a DEXA scan (to establish your current bone health status).

Ultimately, determining whether you’re experiencing RED-S involves looking at the bigger picture. Your training, nutrition and mindset all need to be considered but there are others tools which can help you and your doctor reach a conclusion.

Unfortunately, many GPs will never have heard of RED-S, or will know very little about it if they do. Thankfully, there are a few specialists in this field, and I'm here to point you in the right direction if needed.

How do I know if I have HA?

HA is a ‘diagnosis of exclusion’, meaning a diagnosis is made when all other options have been eliminated. This will involve working with your doctor to rule out any underlying conditions that could be interfering with your periods. You might need to undergo blood tests, an ultrasound or brain scan (to check the functioning of the hypothalamic/pituitary areas), or have a physical examination. Aside from a lack of periods, other signs of HA include very light or irregular periods, low libido (sex drive), constantly feeling cold, feeling down or anxious and having an increased appetite.

Having experienced HA myself, I know how overwhelming this diagnosis can feel. It can also be ambiguous and leave you feeling uncertain what steps to take to get better. After coming through the other side and helping others on their journey too, I now provide advice and support in a mentoring capacity here.