RED-S In Youth Athletics: An Epidemic of Low Energy In Athletes (And How To Address It)

A basketball player wiping his face with a towel.

If I were to hazard a guess, you’re reading this because you, someone you know, or one of your athletes are dealing with RED-S. If you’re here out of sheer curiosity, keep reading. It’s important.

Relative Energy Deficiency in Sport, or RED-S, is a severe problem that can occur in athletes when they don’t eat enough to meet the energy demands of their sport.

Whether you’re a major endurance athlete or simply a gym hobbyist, RED-S can occur in anyone who does not consume enough food to fuel their activity levels, regardless of height, weight, age, or gender.

With so much popular dialogue around caloric restriction and restrictive diets, RED-S can easily sneak up on athletes. Especially those who think they are being healthy when in actuality they are depleting their fuel stores. This could lead to a future of bone density issues, hormonal problems, slow recovery times, impaired performance, and even psychological issues.

Given the potential for long-term damage, vigilance for RED-S is especially important in the arena of youth athletics.

Understanding RED-S as a Facet Of Low Energy Availability

To understand RED-S, first, it’s important to familiarize ourselves with another term: Low Energy Availability (LEA).

Energy Availability is a metric used primarily in sports science to determine an athlete’s ability to fuel their exercise and daily functions. The energy availability score is determined by:

  • Taking your daily calorie intake
  • Subtracting your calories burned from exercise
  • Dividing that number by your fat free mass

When this metric is below 45, you have entered low energy availability. When it is 30 or below, severe side effects can be expected and RED-S becomes a major risk factor.

Avoiding LEA is simply a matter of increasing food intake. It becomes RED-S only when LEA goes on long enough or becomes severe enough that symptoms become chronic and may not easily resolve from increasing caloric intake alone.

Warning Signs of RED-S

Before RED-S was coined as a diagnosis, LEA issues primarily fell under the umbrella of the Female Athlete Triad syndrome.

This term was used to label similar issues to RED-S but with a number of diagnostic problems.

For one thing, the female athlete triad fell under the stigma of eating disorders, causing mildly disordered but not necessarily extreme eating habits to be overlooked as a risk factor. Activity level was also often overlooked.

Furthermore, it relegated concern to female athletes solely, despite the fact male athletes are just as susceptible to mild disordered eating and RED-S.

Another issue was that the female athlete triad relied heavily on the loss of an athlete’s menstrual cycle as an early warning sign. Further study of RED-S has found that loss of one’s menstrual cycle is a late-stage signal, with other signs and symptoms appearing much earlier, never mind the fact this again overlooks male athletes.

Stress Fractures & Osteoporosis

Among the earliest and most concerning warning signs of Relative Energy Deficiency syndrome are stress fractures. Bone density is a major factor in health, athleticism, and longevity, and under normal circumstances, an athletic background is a huge preventative measure against osteoporosis.

However, in the case of RED-S, low energy leads to rapid bone density loss.

This is especially heinous for youth athletes, who are also experiencing puberty and need to be able to build solid skeletal tissue.

Any athlete experiencing stress fractures should be assessed for RED-S and undergo a DEXA bone density scan as soon as possible.

Osteoporosis is a dangerous condition in its own right and a major reason to familiarize yourself with RED-S. Non-weight-bearing sports may be at higher risk of osteoporosis from RED-S, but should still be monitored.

Cycling, swimming, and rock climbing all may be at higher risk of osteoporosis from RED-S.

Also, though technically weight-bearing, long-distance running can be at a higher risk as well. Due to the limited range of motion, running does not promote skeletal tissue growth the way sports like gymnastics, weightlifting, or basketball might.

Alternatively, weight-bearing sports like MMA or gymnastics athletes with RED-S may be less likely to exhibit stress fractures as a warning sign. So, if other signs of RED-S show themselves, a DEXA scan should still be performed to rule out osteoporosis.

Poor Recovery & Hormone Imbalances

The next likely sign of RED-S is simply poor recovery. If athletes exhibit low performance and/or slow recovery from workouts, especially if this is a new sign, they are candidates for RED-S assessment.

Further exacerbating the issue is that RED-S can begin causing hormone imbalances if it goes on long enough. As mentioned earlier, one of the middle to late-stage signs of RED-S in female athletes is the loss of the menstrual cycle.

In men, testosterone can become impacted which may be difficult to correct.

Cramping, Tissue injuries, and Weight Gain

Paradoxically, RED-S can often exhibit weight gain due to a slowing of the metabolism.

Other signs of RED-S can be difficulty building or retaining muscle, and an increase of tissue injuries.

Tendinopathies, general injuries, and cramps may increase in an athlete with RED-S. Keep an eye out for these signs alongside the others mentioned thus far.

Causes of RED-S in Youth Athletes

As we mentioned, RED-S is caused by too low energy to support athletic endeavors. AKA too little food. However, there are nuances to this beyond simple calorie count. Full-blown eating disorders are indeed a risk factor, but overlooked is the case of disordered eating.

Many popular diets for weight loss can influence the athlete to adopt a disordered and unnecessary eating pattern. The vilification of carbs and promotion of fasting may raise the risk of RED-S in athletes, especially youth athletes, who may be overly concerned with appearance.

Furthermore, an overall desire to be lean and “look” like top athletes can contribute to caloric restriction.

Eating Disorders, Fasting, Caloric Restriction, & Keto/Low Carb

A big reason RED-S may occur in athletes is the misconception that weight-loss strategies translate to peak athletic performance. For one thing, weight-loss techniques like extreme caloric restriction are suspect even in that realm. Remember “The Biggest Loser”? Most winners typically revert to their previous weight within a few years.

For two, the glorification of caloric restriction is a recipe for low energy availability in athletes.
Carbohydrate restriction is also a risk factor. Low carb diets and ketogenic diets attempt to replace energy needs with fat, but it takes time to adapt to ketosis and it may have disadvantages for athletic performance even in the well-adapted.

Youth athletes who are trying to engage in high activity alongside low-carbohydrate consumption are likely to overburden their energy needs even if they are getting enough calories.

While carbohydrate quality may be a concern, eschewing carbs is not recommended for athletes, especially in youth athletics.

Furthermore, fasting, whether intermittent or prolonged, can move the body towards RED-S rapidly if daily energy needs are not being met. If you engage in intermittent fasting, it is imperative you measure your daily caloric intake to ensure adequate fueling.

Aesthetic Visible Leanness As A Risk Factor

Another major risk factor for RED-S is the desire to appear hyper-lean and equating aesthetics with performance. In actuality, body fat percentages between 10% and 20% may favor performance in men, and 23%-30% in women.

Whereas lower numbers like those associated with bodybuilders or fitness influencers actually lend themselves to higher rates of injury, lower performance, and the development of conditions like RED-S.

Youth athletes may be especially susceptible to this trap of restricting calories to look more lean, despite the fact it is unhealthy.

Weight-Class Athletics

Sports which are weight-conscious can be a risk factor for RED-S, be it for the sake of the sport itself (rock-climbing where being lower weight is advantageous) or when competitions separate athletes by weight class.

Weight cuts like those in boxing, MMA, and wrestling can be harsh on the body and resemble extreme LEA for short periods. However, the effects can still lead to RED-S and damage metabolism and cause hormonal issues.

Sports where athletes may seek a lower weight are:

  • Cycling
  • Distance running
  • Rock climbing
  • Wrestling
  • Boxing
  • MMA
  • Swimming

Keep an eye out for RED-S in any such sports or activities.

How To Recover From RED-S

If caught early, recovery can be as simple as increasing daily calories for a short period of time. However, if caught late, RED-S can become resistant to simply improving energy availability due to the damage to metabolism, hormones, etc.

In this case, other tactics should be employed alongside energy availability efforts to promote better outcomes from RED-S.

Some examples would be:

  • Improving sleep
  • Nutrient access as well as calories (low nutrient calories can be an issue)
  • Lowering exercise volume
  • Prioritizing high-intensity but short exercise to kick hormones back into gear

Red-S Recovery Tip 1: Get An Accurate Energy Availability Assessment & Adjust Food Intake Accordingly

What gets measured gets managed. And the first step of recovering from RED-S is also the first step in assessing it: Calculate your energy availability.

(Total Daily Calories – Calories Burned During Exercise) / Fat Free Mass = Energy Availability

You can get a medical test of your fat free mass if you want to pinpoint accuracy, but for the sake of this simple assessment just use an online calculator.

To calculate your total daily calories, at minimum, use an app like My Macros Plus or My Fitness Pal to input all the food you eat in a single day. Use a cheap food scale from Amazon to determine weight of unlabeled foods and use the nutrition facts of packaged foods.

Finally, you can figure out your calories burned during exercise by using this chart of average calorie burn in 30 minutes by activity and weight.

Once you’ve determined your energy availability, increase your food intake to get that number above 45, ideally 55-70, from here on out.

If that sounds like an intimidating amount of calculation, here’s my suggestion. Stay to the conservative side. Record your calories on a day where you’re eating more food and doing more activity.

Then, when you get your calculations, significantly increase your calorie intake and calculate again. When in doubt, eat more.

Don’t be afraid of weight gain if you are dealing with suspected RED-S. The negative effects on your metabolism from being in a state of low energy availability is more likely to cause weight gain in the first place. Focusing on quality and otherwise trying to increase calories is the way to go here.

Generally, seek adequate protein (30% of daily calories or so) and aim for 30-50% carbohydrate and the remainder fats.

Some tips for consuming nutritionally dense foods:

For more calories, yams, sweet potatoes, and squash are good options. White rice can also be a great way to up your calories if you’re having a hard time, but it is low in nutrients so make sure to eat a varied diet elsewise.

We love the Primal Kitchen brand for good dressings and fats.

Once you get your score up, maintain it and focus on other tools to support hormonal health like sleep and occasional, short, high intensity movement. Consider reducing exercise volume at-large.

Red-S Recovery Tip 2: Sleep To Get Strong

Sleep is your biology’s numero uno recovery process. It’s the only time your brain cleans itself (look up the glymphatic system to have your mind blown) and it’s when we process the memories of the day and dream.

You’d be hard-pressed to find a better super-power than perfect sleep every night. And this goes doubly for anyone recovering from a condition like RED-S.

Here at The Ready State, we’re big proponents of sleeping 8 hours a night which may mean being in bed for ten.

Other key points to consider are:

  1. Sleep at the same time. More specifically, based on the research, you should go to bed within an hour of the same time every night, and you should wake at the same time every morning.
  2. Follow your chronotype if you can. Your chronotype is your genetically based sleep rhythm. It dictates when you will have the easiest time going to bed and waking up. You can guess your chronotype using this quiz, or by getting your health reports from 23andme if you’ve purchased your genetic information.
  3. Explore the possibility of sleep apnea and reduce the odds with Mouth Tape. Sleep apnea means getting too little oxygen while sleeping and has a host of negative health effects.

Beyond these big 3, you can radically improve sleep outcomes by using a few basic tips.

  • Leave the electronic devices out of your room an hour before bed. The Kitchen Safe is a great device for locking away gaming controllers and even cell phones. Don’t worry, if an emergency does occur, you can easily bust it open without damaging the time lock lid, though you will need a replacement base. Studies have found that those who use their phones in bed fall asleep an average of 90 minutes later and have worse sleep quality than those who do not.
  • Write a to-do list for the coming day before bed. It’s been shown that a detailed to-do list helps you fall asleep faster. The more detailed, the greater the effect.
  • Increase non-exercise movement throughout the day. Here at The Ready State, we often observe that sleep problems for athletes may be a simple result of not enough non-exercise movement during the day. I’ll talk about this more in the next section on Movement and Exercise for RED-S, but understand that simply walking more during the day can help sleep.
  • Cold shower 2-3 hours before bed. While taking a cold shower right before bed can be too energizing, it does trigger parasympathetic nervous system reactions making sleep and relaxation easier. Try a cold shower a few hours before bed. One easy method is to do hot water for 10 seconds, then cold for 20. After 5-10 rounds, end on cold. A hot bath or sauna is also great for sleep.
  • Mobilize before bed. We recommend 10 or more minutes of mobility work per day to improve and maintain movement health. Mobility work is also great at downregulating the nervous system. Doing your daily mobility work in the evening, whether just after the workday or immediately before bed, can be great for improving sleep outcomes.

Finally, if you suffer major sleep issues or these tips don’t work, you could work with a medical professional to find natural or prescription sleep aids that are safe for you or your child.

Exercise & Movement Adjustments For Resolving RED-S

First and foremost, reducing exercise volume is the beginning step for resolving RED-S. After all, we want to increase our energy availability which can be done by increasing fuel or reducing exercise.

But there’s more to this puzzle.

While we want to lower energy expenditure for a RED-S athlete, we still want to improve hormones and build and maintain muscle if possible. In essence, we want to keep our exercise signals powerful and robust even while lowering the training load.

Sprint Work

One of the best ways to do this is by utilizing true high-intensity interval training. For clarity, I’m not talking about exercise classes like Orange Theory or even CrossFit, which claim to be HIIT but actually fall much more into the medium intensity category and can be very fuel-depleting.

I’m talking about sprint work, meaning very short bursts of the highest intensity followed by 3-5 minute or longer rest periods. And since RED-S athletes may be more at risk of impact injury, a rowing machine or assault bike is a wonderful tool here.

At a minimum, you could reduce an athlete to only one session per week of sprint work during recovery.

Perform 4 rounds of 30-second sprints on an assault bike followed by 3 to 5 minutes of rest.

Next, we want to build or at least maintain muscle.

Eccentric Training

One way to build strength with less strain is by doing very slow reps, also known as eccentric training.

The Body by Science workout was designed by Doug McGuff and colleagues to help elderly individuals gain muscle steadily and reliably with minimal energy demands. Since its advent, thousands of athletes of all ages have utilized it to build muscle in a single, weekly 12-minute session.

You could also perform the Body by Science routine while wearing BFR bands, as the two modalities fit each other quite well.

Each exercise is performed slowly, taking 6-10 seconds per rep. Aim for 9-15 reps which should be about 90 seconds of time under tension depending on your cadence. There are 5 exercises total, which are meant to be performed as one round each with no break between exercises.

Here is a bodyweight version of the Body by Science workout:

  1. Slow pushups
  2. Slow pull-ups (band-assisted)
  3. Slow pike press
  4. Slow ring rows
  5. Slow squats

You can use this structure with weights as well by replacing these exercises with exercises that utilize the same muscle groups. Bench presses rather than push-ups, and lat pulldowns instead of pull-ups. Etc.

Non-Exercise Movement & Mobility Work

Similar to just not eating enough, at The Ready State we often see that athletes just don’t move enough.

This can be especially true of youth athletes, who spend large portions of the day seated in classrooms. While the somewhat regular breaks to walk to one’s next lesson are helpful, for the RED-S athlete, focusing less on exercise and more on movement is a big point of interest.

We recommend aiming for 8000 steps per day and more if you can. If you have trouble with exercise due to RED-S, spending a few weeks or more solely focusing on long walks as often as possible can be a great onboarding ramp for returning to the gym.

The easiest way to start this process is to go for a half-mile or a one-mile walk daily upon waking, or after school. Pick one and make it your “line in the sand”.

Mobilize More

Mobility work is great for Relative Energy Deficiency prevention. Remember, we want to get as much movement in while also supporting our parasympathetic nervous system response. It’s common for RED-S athletes to exhibit signs of chronic sympathetic, or fight or flight, nervous system activation.

Mobilizing not only aids the body by making you, well, more mobile, but it downregulates the nervous system and promotes recovery.

During 2020, Kelly ran a daily downregulation class (still available in the bonus section of the Virtual Mobility Coach app) every day at 5 pm for the explicit purpose of helping people weather the stress storm of lockdown. Being that you may be forgoing some of your old workouts, I recommend at least replacing them with 20 to 30 minutes of mobilization.

Our daily maintenance routines on The Virtual Mobility Coach are perfect for this.

Beat RED-S By Knowing What To Look For

RED-S is the kind of condition that can ruin lives, no joke, but thankfully it is getting more recognition, and the signs are easy to spot if you know what to look for.

Fundamentally, RED-S is an epidemic of the wrong mindsets around food when it comes to health and performance. Athletes need to make sure they are eating enough to sustain their activity level.

With youth athletes in particular, weight-loss eating strategies are often used to pursue more visible leanness and to try to improve performance, when in reality, these athletes may need to eat more.

By addressing misconceptions around the relationships between food, body fat percentage, health, and performance, we can help our athletes avoid the myriad hormonal, metabolic, and osteoporotic consequences of RED-S.

Keep an eye out for signs like stress fractures and low recovery. Change the conversation around food. And help your athletes see that weight-cuts, excessive fasting, and a sub-10 percent body fat percentage are neither necessary nor helpful for health and performance.

Don’t let RED-S sideline your athlete. Get customized mobility coaching developed by Dr. Kelly Starrett to ensure they’re fueled for optimal performance and long-term health.

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