Athletic Amenorrhea/RED-S
What is Athletic Amenorrhea/RED-S?
Athletic amenorrhea is the absence of menstrual periods in female athletes. It happens when intense training combines with inadequate nutrition. Your body essentially shuts down reproduction to conserve energy for survival.
This condition is part of a larger syndrome called Relative Energy Deficiency in Sport, or RED-S. RED-S affects metabolism, bone health, immunity, protein synthesis, and cardiovascular function. When you burn more calories than you consume over time, your body goes into conservation mode. Leptin is a hormone that signals your energy status to your brain. Low leptin levels tell your brain that fuel is scarce, which triggers the shutdown of non-essential systems like reproduction.
RED-S affects athletes in all sports, but it is most common in endurance sports and activities that emphasize leanness. Runners, dancers, gymnasts, swimmers, and cyclists face higher risk. Male athletes can also develop RED-S, though amenorrhea only affects females. The condition is reversible with proper nutrition and adjusted training, but early detection matters for long-term health.
Symptoms
- Missed periods for three or more consecutive months
- Never having started a period by age 15
- Decreased training performance or constant fatigue
- Frequent injuries or stress fractures
- Poor concentration and irritability
- Cold intolerance and always feeling chilly
- Dizziness or fainting during exercise
- Hair loss or thinning
- Decreased muscle strength despite training
- Digestive issues or constipation
Many athletes dismiss these symptoms as normal side effects of hard training. Some may not realize that losing your period is a serious medical issue. Early stages may feel subtle, making it easy to ignore warning signs until bone damage or other complications develop.
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Causes and risk factors
Athletic amenorrhea develops when energy intake is too low for your activity level. This creates a state called low energy availability. Your body needs a minimum amount of energy for basic functions after accounting for exercise. When that threshold is not met, leptin levels drop. Low leptin signals starvation to your brain, which suppresses reproductive hormones like estrogen, luteinizing hormone, and follicle-stimulating hormone. Without these hormones cycling properly, ovulation and menstruation stop.
Risk factors include sports emphasizing thinness or weight categories, high training volume without adequate fueling, disordered eating patterns, perfectionism, and pressure from coaches or peers. Some athletes restrict food intentionally for performance or appearance. Others simply underestimate their calorie needs or feel too full to eat enough. Body composition goals that are too aggressive or rapid weight loss also increase risk. Genetics may play a role in individual susceptibility to low energy availability.
How it's diagnosed
Diagnosis starts with a medical history and physical exam. Your doctor will ask about menstrual patterns, training volume, nutrition habits, and symptoms. Blood tests help confirm the diagnosis and rule out other causes of missed periods. Leptin testing reveals low energy availability, which is the root cause of athletic amenorrhea and RED-S. Low leptin combined with high activity levels and absent periods points directly to this condition.
Additional tests may include thyroid hormones, estrogen, luteinizing hormone, follicle-stimulating hormone, and prolactin. Bone density scans assess whether low estrogen has already damaged your bones. Rite Aid offers leptin testing as an add-on to our flagship health panel. You can get tested at over 2,000 Quest Diagnostics locations nationwide. Understanding your leptin levels helps you and your doctor create a recovery plan based on your actual energy status, not guesswork.
Treatment options
- Increase daily calorie intake to match your training demands and support basic body functions
- Work with a sports dietitian to calculate your energy needs and create a realistic meal plan
- Reduce training volume temporarily while your body recovers hormonal balance
- Gain weight if you are below a healthy body mass index for your height and frame
- Address any disordered eating patterns with a therapist specializing in athletes
- Monitor leptin levels and other hormones to track recovery progress
- Consider short-term hormonal birth control only as a last resort, not as first-line treatment
- Focus on nutrient-dense foods including adequate protein, healthy fats, and carbohydrates
- Allow time for natural menstrual cycles to return, which can take several months
- Work with your coach to adjust training philosophy around fueling and recovery
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Frequently asked questions
Athletic amenorrhea is one symptom of RED-S, which stands for Relative Energy Deficiency in Sport. RED-S is the broader syndrome that affects multiple body systems when energy availability is too low. Amenorrhea specifically refers to the loss of menstrual periods, while RED-S includes metabolic, bone, cardiovascular, and immune dysfunction. If you have athletic amenorrhea, you likely have RED-S affecting other areas of your health as well.
Period return varies by individual and depends on how long you have had amenorrhea. Some athletes see periods return within three to six months of adequate fueling. Others may need a year or longer, especially if bone density has decreased significantly. Consistent positive energy balance and weight restoration are key factors. Monitoring leptin levels helps track whether your energy status is improving.
Yes, but training volume and intensity usually need to decrease during recovery. Your body needs surplus energy to restore hormonal function, not just enough to maintain current weight. Work with your coach and medical team to find a balance that supports health while maintaining fitness. Many athletes fear losing conditioning, but the performance gains from full recovery outweigh temporary training reductions.
Birth control creates an artificial bleed, but it does not fix the underlying energy deficiency or restore natural hormones. Taking birth control can mask the problem and delay proper treatment. It also makes it harder to know when your natural cycle returns. Birth control may be appropriate in specific cases, but it should not replace adequate nutrition and reduced training as first-line treatment.
Ignoring athletic amenorrhea leads to serious long-term consequences. Low estrogen weakens bones, increasing fracture risk that may never fully reverse. You may develop early osteoporosis, even in your 20s or 30s. Cardiovascular health suffers from hormonal imbalances. Fertility problems can develop if the condition persists for years. Early intervention prevents permanent damage to your bones and overall health.
Signs of adequate fueling include regular menstrual cycles, consistent energy throughout the day, good recovery between workouts, and stable weight. A sports dietitian can calculate your specific energy needs based on your training load and body composition. Tracking leptin levels provides objective data about your energy status. If your period is missing or your performance is declining despite training, you are likely underfueling.
Yes, male athletes absolutely develop RED-S from low energy availability. They experience low testosterone, decreased libido, poor bone health, frequent injuries, and declining performance. Because men do not have the obvious warning sign of losing their period, RED-S often goes undiagnosed longer in males. Leptin testing helps identify low energy availability in both male and female athletes.
No, losing your period is never normal or healthy, even with intense training. It is a clear sign that your body lacks adequate energy for both exercise and basic functions. Many coaches and athletes incorrectly view amenorrhea as a badge of dedication. In reality, it signals that your training approach is damaging your health and will eventually hurt your performance.
Focus on eating enough total calories first, then prioritize quality. Include adequate carbohydrates to fuel training and support leptin production. Add healthy fats from nuts, avocados, olive oil, and fatty fish to support hormone production. Ensure sufficient protein for recovery and muscle maintenance. Do not fear weight gain, as some restoration may be necessary for menstrual function to return.
Testing leptin every three to six months helps track whether your energy status is improving. Initial testing establishes your baseline. Follow-up tests show whether increased food intake and reduced training are working. Rising leptin levels indicate positive energy balance and suggest hormonal recovery is underway. Your healthcare provider can recommend the best testing schedule based on your individual situation.