So you're an athlete, welcome - we're so glad you're here. Chances are, you have a problem you want to fix. Maybe you’ve been having trouble adapting to training lately; you might feel generally fatigued; or perhaps your period's been missing for a while now. At first, maybe you were okay with that...but recently you can’t shake the feeling that something’s just, ‘not quite right’. If that’s the case, you’re right (it isn't) and we want to explain why and what you can do about it.
RED-S stands for Relative Energy Deficiency in Sport and is exactly what the 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).
'Low energy availability’ describes the negative balance (whether intentional or unintentional) between energy intake and expenditure (i.e. food consumed vs physical exertion). When this balance is tipped over a period time, the body goes into 'energy saving mode' which negatively affects almost every system in the body.
One concerning effect of RED-S is suppression of hormones within the reproductive system which can result in one big red flag among females: irregular or missing periods. That said, RED-S can affect athletes or exercisers of any age, gender, ability, size or weight and carries serious long-term health and performance implications.
Almost any athlete, exerciser or dancer - male or female - whose expends energy through sport can be at risk of RED-S - from recreational runners to Olympic gymnasts. Athletes from endurance sports or those which promote a low body weight (e.g. for aesthetics or performance) tend to be at the greatest risk for two main reasons.
1) Endurance sports, by nature, demand a lot of energy which can easily be underestimated
2) Where there are pressures to look a certain way or achieve a certain weight, athletes are more likely to manipulate food intake 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 these athletes most susceptible to RED-S.
Quite simply, RED-S is the result of consistently consuming insufficient calories for the amount of energy you expend, either intentionally or unintentionally. There are many different factors which can contribute to the development of RED-S, including:
- Intentionally restricting calories – e.g. to meet body composition goals or lose weight
- Unintentionally underestimating the energy requirements of training/competition
- Not matching an increase in training with a corresponding increase in caloric intake
- Lack of appetite or gastrointestinal distress (upset tummy) leading to less food consumption
- Moving to university or somewhere new and increasing active travel on foot/bike, having to cook own meals, changes in training types/frequency/intensity, wanting to focus on being ‘healthier'
- As a result of disordered eating behaviour or a clinical eating disorder
Regardless of the cause, we can't stress how important it is to identify any potential causes early on. The chances of recovery from RED-S are significantly increased with early identification and treatment.
RED-S is typically diagnosed by a sports specialist via blood tests, sometimes a DEXA scan (to establish your current bone health status) and an assessment of your relationship with training and nutrition. Unfortunately, RED-S has been under recognised in medical training so many doctors may not be clued up on the condition.
However, whilst every individual is unique, there are a number of common symptoms that you can look out for yourself. However, many of these symptoms are subtle and therefore easy to ignore, so it's essential to be honest with yourself. Even if your routines and diet seem to be sustaining you at present, dismissing any symptoms of RED-S (no matter how minor at this stage) can be extremely damaging in the longer-term.
Ultimately, diagnosing 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. We've recommended a few specialists you can go to for help, here.
Yes! Missing/irregular periods and stress fractures are just two potential symptoms and are, by no means, a prerequisite for RED-S. This condition affects all genders and there are always individual differences in the body's response to low energy availability. Although some degree of menstrual dysfunction is common, it won’t be a symptom among males (obviously!), those who aren’t old enough to have started a menstrual cycle, or those who have been through the menopause. Females using hormonal contraceptives also won't know whether they have menstrual dysfunction since these work to suppress the natural menstrual cycle. Read more about this here. A lack of morning erection is an equivalent red flag sign for men.
Yes! RED-S can affect athletes of all shapes and sizes, yet one common misconception surrounds not being ‘thin enough’ to suffer. Since everyone responds to an energy deficit differently, you can absolutely experience RED-S while remaining within (or even above) what society deems to be a ‘normal’ or 'healthy' weight. Our bodies are naturally programmed to protect themselves from perceived starvation by compensating (e.g. decreasing our metabolism) so some people may not lose weight, even in the face of severe low energy availability.
RED-S is not limited to athletes with eating disorders, or any form of disordered eating. A deficit is created by a mismatch between energy consumed (through food) and energy expended (through exercise) on top of everyday functions (growth, respiration, digestion, etc). It doesn’t matter how this occurs, the result is the same. Common scenarios where this can happen unintentionally include:
- Simply under-estimating the amount of nutrition required to cover the demands of your active lifestyle
- When your training load or intensity is increased and not matched with increased calories
- When you're busy balancing the demands of training with studies/work/social activities and these distractions get in the way of fuelling adequately
- When your appetite is suppressed for various reasons including exercise itself (though more scientific research on this is required)
The symptoms of RED-S often overlap with those of the 'Female Athlete Triad' which, as the name suggests, focusses only on females and comprises three inter-related parts: insufficient energy intake, amenorrhea (missing periods) and decreased bone density. However, part of the International Olympic Committee's goal in coining the term 'RED-S' was to highlight the fact that low energy availability impacts males as well as females, alongside those who don’t necessarily define themselves as ‘athletes’. And, whilst menstrual function and bone health are often both impacted by low energy availability, the term RED-S describes a far broader range of physiological and psychological consequences across both genders.
Recovery from RED-S involves recognising where you may have gone wrong with your fuelling and then doing what it takes to correct it. We've stocked this site with all the tools we think you'll need; our only ask is that you keep an open mind to everything you read. If you're here to correct unintentional nutritional mistakes, or because somewhere along the way you fell into the trap of intentional restriction, we're here to help you change that.
‘Amenorrhea’ is the term used to describe the loss of a menstrual cycle. It's 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
A diagnosis of Hypothalamic Amenorrhea (HA) is made when all other potential causes 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.
Worryingly, missing periods are often normalised within sport settings but in either scenario, amenorrhea should be taken seriously. Many athletes, coaches, parents and even doctors seem to miss the crucial link between amenorrhea and an energy deficit, which can lead to prolonging the condition. Yet more worryingly, doctors are even likely to encourage use of the Contraceptive Pill, rather than investigate the underlying cause. This is why it is so crucial to take ownership of the situation and educate yourself about the impact of an energy deficit on your hormones.
The short answer is, you won't. Hormonal contraceptives (including the Pill, the Patch, the NuvaRing, the Mirena IUD, Depo-Provera and Implanon) work by suppressing the body's natural menstrual cycle, so you won't be able to tell if you have one while using them. Getting a better grasp of whether you have natural periods would involve using a different form of non-hormonal birth control (including the copper intrauterine device (IUD), condoms, cervical caps, femidoms, and spermicidal gels and 'natural cycles') for a while to see if your natural menstrual cycle resumes. We would highly recommend seeking support from a sports doctor or RED-S specialist when it comes to this topic, since regular medical practitioners are unlikely to have the knowledge required to best advise an athlete.
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.
We know how overwhelming and isolating all this information can feel - especially when you're struggling to find someone who can help. RED-S has been under recognised in medical training so many regular doctors may not be clued up on the condition. If this is the case, it’s crucial not to get disheartened and give up on exploring the issue further. This biggest mistake you could make at this point is believing that you're fine - or that if you just carry on doing whatever you're doing, your health and performance goals will come back within reach. We've done our best to make things as easy for you as possible by creating a list of support resources and a page about talking to your doctor. We're continually updating our list of resources, so please do help out by popping a comment below with any recommendations you may have.
Wherever possible, the information and advice offered on this site is based on the leading scientific research to date. Although the aim is to provide you with some support and advice, this resource is no substitute for the diagnosis or treatment from a medical professional. Head here to find them.