RED-S: The Silent Threat Every Athlete Should Know About
- Megan Whitehouse
- Jun 27
- 4 min read
Feeling Tired, Slower, or Off Your Game?
It Might Be RED-S
Training hard but not seeing results? Constantly exhausted, moody, or getting injured? You might be dealing with Relative Energy Deficiency in Sport (RED-S) a condition that’s more common than you think.
RED-S can impact your performance, health, hormones, and recovery-but the good news is, it’s reversible.
What Is RED-S?
RED-S happens when there’s not enough energy (food) coming in to support both your training and basic bodily functions. It’s like trying to run your phone on 5% battery-eventually, things shut down.
And no, RED-S isn’t just a problem for elite athletes or those with eating disorders. It can affect anyone: runners, lifters, dancers, weekend warriors.
Why Athletes Underfuel (Even Without Realising It)
RED-S is usually caused by under-fueling in athletes, whether it’s intentional or not.
Some common reasons include:
Skipping meals due to busy schedules
Restrictive diets or weight loss goals
Not eating enough to match training demands
Fear of weight gain or "eating too much"
Poor recovery nutrition
You don’t have to be underweight to be underfueled. Even athletes at a healthy or high weight can experience low energy availability.
How RED-S Impacts Your Body & Performance?
The Physical Side Effects
Constant fatigue or burnout
Slower recovery and frequent injuries
Missed periods in female athletes
Low libido or testosterone in men
Stress fractures or bone loss
Digestive problems like bloating or constipation
The Mental and Emotional Toll
Mood swings and irritability
Anxiety or depressive symptoms
Brain fog and poor concentration
Loss of motivation to train
If you’ve noticed athlete fatigue that doesn’t improve with rest, RED-S might be the cause.
Common RED-S Symptoms
You might be dealing with RED-S if you’re experiencing:
Always feeling tired
Decline in performance
Recurring injuries
Missed or irregular periods
Poor recovery
Mood changes
Trouble sleeping
Loss of interest in training
Digestive issues
Low sex drive
RED-S in Female Athletes: It’s More Than Missing Periods
A common misconception is that RED-S only affects women who stop getting their period. But RED-S in female athletes can show up in other ways too:
Irregular cycles
Cold hands and feet
Hair thinning or dry skin
Difficulty building strength
If you’ve lost your period, it’s not just “part of being an athlete.” It’s a red flag.
RED-S in Men: What to Watch For
Men are often overlooked in RED-S conversations; they’re at risk, too.
Signs of RED-S in male athletes may include:
Low testosterone or sex drive
Trouble maintaining muscle
Poor sleep or mood changes
Decreased performance despite training hard
If you’re constantly training but not seeing gains, RED-S could be to blame.
Why Early Detection Is Key?
Catching RED-S early can prevent long-term health problems like:
Bone density loss
Hormone imbalances
Immune system issues
Chronic fatigue
Performance decline
You don’t need to wait for things to get “bad enough.” If you’re concerned, now is the right time to act.
Book a consultation with a sports dietitian to start your recovery.
How to Start RED-S recovery?
1. Eat More
Recovery starts with restoring energy availability. That means fueling your body with enough food to meet your needs-training, recovery, and daily life.
Tips:
Add snacks between meals
Prioritise post-workout carbs and protein
Don’t skip breakfast
Include healthy fats such as olive oil, eggs, chia seeds as support hormones
2. Adjust Your Training Load
You may not need to stop training completely-but scaling back intensity or volume temporarily can help your body catch up.
Recovery isn’t quitting. It’s a strategic move to come back stronger.
3. Rethink the “Lighter = Better” Mentality
Many athletes fear that eating more will hurt performance or cause weight gain. In reality, proper fueling boosts strength, endurance, and mental focus.
Food is fuel, not something you need to “earn.”
4. Get Support
Recovering from RED-S isn’t something you need to navigate alone. A support team may include:
A physician (especially for hormone or bone health)
A therapist (for disordered eating or body image issues)
A coach who understands athlete health
FAQ: Quick Answers About RED-S
Can you have RED-S and still look “fit” or healthy?
Yes. RED-S isn’t about how you look-it’s about what’s happening inside your body. Even lean, muscular, or high-performing athletes can be underfueled.
Is missing a period a normal part of training?
No. Missing periods is not normal. It’s a sign that your body is under stress and not getting enough energy.
Can I keep training while recovering from RED-S?
Maybe. It depends on your symptoms. Some athletes can continue with modified training, while others need more rest. The best plan is personalised and guided by a professional.
Don’t Wait-Take Action Now
If you’ve read this far and something resonated… it’s time to check in with yourself. Ignoring RED-S won’t make it go away-and pushing through will only make things worse.
Here at Nutrition &Co we believe you deserve to feel strong, energised, and healthy. Let’s get you back to performing your best.. For 1-1 nutritional advice with the world’s leading sports and health nutritionists, Book your FREE Discovery Call here.
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