As an athlete, you try to strike the right balance of diet and exercise to prepare your body to perform at its best. It’s not easy to balance food intake with exercise, but it’s extremely important. If your body doesn’t have enough fuel, you’ll find it impacts both how you perform and your overall health.

Relative energy deficiency in sport (REDs or RED-S) is a syndrome with concerning symptoms that include fatigue, mood changes and an increased chance of injury. Below, we share more about REDs symptoms and how to keep it from affecting your performance and, more importantly, your physical and mental health.

What is relative energy deficiency in sport? A syndrome that can impact athletic performance and overall health

If an athlete continues to push their body without properly refueling, it creates an energy deficit. This means that the athlete is burning more calories than they eat, and because of this, their body isn’t able to recover.

It’s important to note that your body tends to preserve fat for protection. When your body isn’t getting the fuel it needs from the outside, it won’t immediately take the extra calories from fat. Instead, it will aim to get calories from protein first, and your muscles make an excellent source.

REDs syndrome can affect amateur and professional athletes of all genders. Female athletes who develop REDs may develop something called the female athlete triad.

REDs vs. the female athlete triad

You may have heard of the female athlete triad and wonder how it’s different from REDs syndrome. The female athlete triad is a subset of REDs and is sometimes used to describe a collection of symptoms that appear together in highly active female athletes. These symptoms relate to energy availability, menstrual function and lower bone density. The female athlete triad syndrome was first recognized in the late ’90s.

REDs is a newer diagnosis. The term relative energy deficiency in sport and the acronym REDs were coined in 2014 by the International Olympic Committee for two reasons:

• Males can also develop symptoms related to an energy deficit.
• The health impacts of under-fueling are complex and can affect people in additional ways beyond those called out as part of the female athlete triad.

Signs and symptoms of REDs syndrome to look for

Your body and brain need fuel to stay active and healthy. If you’re not eating enough food to fuel your body, you won’t be able to perform at your peak. And it’s likely to impact your overall health. Athletes experiencing REDs can feel a variety of physical and mental symptoms, including:

• Fatigue – It can seem like you’re tired all the time or that it’s impossible to stay awake.
• More injuries – People with REDs are more likely to injure their bones, muscles and tendons. Stress fractures are especially common. Lower bone mineral density is one reason male and female athletes are more likely to get injured.
• Poor coordination – Reduced muscle strength can lead to poor coordination.
• Trouble focusing – If your body isn’t getting enough fuel, it can be hard to concentrate or make sound decisions.
• Physical changes – Possible changes include dry skin, hair loss, weaker bones and muscle loss.
• Reduced immunity – It can seem like you’re getting more infections or have a cold or flu all the time, and that it takes longer than usual to get over them.
• Mental health concerns – Increasing moodiness and irritability are common. REDs can also lead to depression, anxiety and other mental health concerns.
• Low hormone levels – Having an energy deficit can greatly affect hormone levels, including estrogen and testosterone. Low hormone levels can affect sexual function, mood and sleep. They can also cause physical changes like weaker bones and muscles.
• Female reproductive health impacts – Females may have delayed puberty or irregular menstrual cycles. While a skipped period may seem convenient, having regular periods is a sign of good overall health.
• Lower sex drive – People with REDs often have low libido.

Without treatment, REDs can lead to serious health issues

Left without treatment, REDs can lead to serious long-term problems, including:

• Amenorrhea – This is a condition where your period stops completely due to low levels of estrogen.
• Osteoporosis – Low hormone levels affect bone density and can lead to osteoporosis at an earlier age. Osteoporosis makes broken bones more likely and can lead to other symptoms, including pain and changes to the way you walk and move.
• Cardiovascular issues – REDs can change the rhythm of the heart and cause a slow heartbeat. Over time, this may result in long-term damage to the heart.
• Changes in metabolism and appetite – Since REDs affects metabolism and appetite, it can lead to unintentional weight loss or weight gain. Loss of appetite can affect nutrient intake and lead to deficiencies in vitamins and minerals.
• Endocrine dysfunction – REDs can affect thyroid function, leading to hormonal imbalances and symptoms like fatigue and changes in weight.

What causes REDs? Consistently low energy availability

Low energy availability happens when you don’t eat enough to keep up with the calories burned during training sessions or competition. Over-exercising can also contribute to low energy availability.

Low energy availability can affect sports performance and the bodily systems responsible for breathing, blood flow, digestion and more. This can be reversed with a proper diet and rest before it turns into REDs. But if a body is consistently under-fueled, it can lead to REDs.

Under-fueling can be intentional or accidental

Under-fueling happens any time the energy you take in through eating is less than the energy you put out through exercise. In some cases, under-fueling can be unintentional – for example, an athlete may forget to eat or they may cut their calories because they don’t understand how much energy their body needs. Intentional under-fueling would be when an athlete chooses to eat less than they know they should.

Under-fueling can also happen if you’re not eating the right balance of foods. In order to function properly, your body needs a variety of nutrients, including protein, fat and carbohydrates. Strictly limiting the types of food you eat can cause low energy availability.

Athletes that are more likely to develop REDs syndrome

Athletes of all ability levels and sports can get REDs. But it’s more likely when there’s a team or sport culture that revolves around weight and appearance, especially if athletes are shamed for their body shape or size.

• Sports that favor an ultrathin figure – An athlete may be more likely to develop REDs if they participate in sports like gymnastics, dance and figure skating, where a lean figure is perceived as desirable.
• Sports with frequent weigh-ins – Athletes who participate in sports like wrestling or boxing are more likely to under-fuel so they meet weight requirements.
• Endurance athletes – Marathon runners, cyclists and other endurance athletes also experience REDs at high rates. Their caloric needs may be higher than they realize, and they may not refuel frequently enough.

Having an eating disorder can make REDs more likely

REDs isn’t an eating disorder, but if an athlete has an eating disorder like anorexia or bulimia, they are more likely to develop REDs. On the other hand, many athletes with REDs do not have an eating disorder.

An eating disorder is a mental health condition related to self-image and self-worth. A person with an eating disorder may have an intense fear of gaining weight or “becoming fat” which can lead to eating behaviors like restrictive dieting, bingeing and purging. If a person has REDs, they may under-fuel on accident or because they don’t know how much they need to eat.

Both REDs and eating disorders are serious conditions that need to be treated. If you’re not sure if you have REDs, an eating disorder or both, make an appointment with a sports medicine doctor or a registered dietitian. If needed, they can refer you for care for an eating disorder.

Steps you can take to prevent REDs

Caring for your body’s needs and being part of a supportive environment are essential to reduce your risk of developing REDs. Here are some things you can do to maintain sports performance and overall health:

• Keep your body fueled – Try to eat enough to support your activity levels, and make sure your diet has enough fats, carbohydrates and protein.
• Take time to heal – Give your body time to recover and heal between training and after injuries.
• Find a supportive environment – Do your best to remove yourself from toxic training environments where you might experience body shaming by a coach or fellow athlete.
• Get help – If you’re not sure what or how to eat to keep your body fueled for sports performance and overall health, find someone to help. This could be a coach, a registered dietician or a sports medicine doctor.

How REDs is diagnosed

To diagnose REDs, the doctor or dietician will ask you about your medical history, symptoms, training routine and eating habits. They will also ask if there has been any change in your sports performance. It’s likely that your doctor will also perform a physical exam to check your vitals.

Treatments for REDs

A main focus of treating REDs is to increase the calories that you eat in order to make sure your body has the fuel it needs. Dietitians can help increase your calorie intake and create eating plans to ensure you get the energy you need to support your training.

A sports medicine doctor can work with you to treat other symptoms caused by REDs. If you need additional specialty care, a sports medicine doctor can connect you with a therapist, OB-GYN or other experts as needed.

If you think you might have relative energy deficiency in sport, we can help

As part of our sports medicine program, we treat athletes of all levels, whether they’re training, performing or recovering. Our team of experts includes sports medicine doctors, physical therapists, athletic trainers and sports dietitians with specialized training in caring for athletes. We also have a special women’s sports medicine program designed to support the unique needs of female athletes.

If you think that under-fueling is affecting your health or sports performance, let us know. We’ll work with you to develop a plan that’s tailored for your activity levels and energy needs.