If you’re an athlete, losing your period for a while might not seem like a big deal. After all, this issue is quite common, affecting nearly 60% of female athletes, with some estimates as high as 80%.
Here are the facts: Losing your menstrual cycle due to overtraining or undereating isn’t “normal.” It’s a symptom of relative energy deficiency in sport (RED-S), a syndrome that can cause long-term health issues. Henry Ford Health primary care sports medicine physician Juliana Molosky, M.D., explains why this happens, how it affects your health and what to do about it.
Why Do Female Athletes Lose Their Periods?
Your body needs the right balance of energy intake (calories you consume) and energy output (your activity level). In other words, you have to eat enough to fuel your training and everything your body does to keep you alive and well. If you don’t have enough energy, you go into a low energy intake (LEI) state, which can lead to RED-S.
“RED-S is a result of an energy imbalance,” says Dr. Molosky. “Your body needs energy to support all of its functions, whether that’s menstruation, immunity or running a 10K. When your training level exceeds your available energy, your body has to pause some of its jobs.”
For females, this often means periods take a hiatus. “To have a period, your hormone levels change at specific times,” says Dr. Molosky. “Low energy availability can lead to your body not producing enough of the necessary hormones involved in your cycle.”
In some cases, RED-S occurs in athletes with an eating disorder like anorexia or bulimia. It can also affect athletes who experience orthorexia, or an extreme concern about healthy eating. But this issue can also affect people without eating disorders who simply don’t realize they’re not getting enough calories for their needs.
Can Low Energy Intake Harm Athletic Performance?
Many athletes think that if they eat less and train harder, they’ll perform better, but this usually isn’t the case. “A lack of necessary calories depletes your speed, strength and training response,” says Dr. Molosky. “Not eating enough for your sport doesn’t improve your performance—it harms it.”
But it’s not just about the sheer number of calories. The type of calories you eat also matters. “We hear a lot about eating protein for muscle building, but carbs are just as important,” says Dr. Molosky. “When you’re exercising, most of your energy comes from carbohydrates. Be cautious with low- or no-carb diets because they may not provide the energy your body needs for your sport.”
Signs of RED-S and Low Energy Intake
A missed period (or periods) during training is often a red flag for RED-S, but it’s not the only indicator. Other signs include:
- Anxiety or depression
- Bloating and constipation
- Decreased coordination, speed and performance
- Fatigue that won’t go away
- Poor recovery after training
- Stress fractures (tiny bone breaks due to repeated activity)
- Stunted growth in children
- Trouble falling or staying asleep
- Weight loss, including loss of muscle
Can RED-S Cause Long-Term Health Issues?
RED-S isn’t just a temporary problem. A lack of sufficient calorie intake can lead to serious health issues, including:
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- Fertility issues
- High LDL (“bad”) cholesterol
- Heart disease
- Impaired growth and development in children and teens
- Osteoporosis (low bone density)
- Trouble with memory, concentration and decision-making
- Urinary incontinence (inability to hold urine)
What to Do if You Think You Have RED-S
If you suspect you or your child could have RED-S, see your healthcare provider. They may recommend a specific meal plan or training schedule. In many cases, RED-S recovery will start once you begin consuming more calories or cutting back (even a little) on physical activity.
“Adjusting your training intensity or calorie intake can help you get back to your optimal energy balance, but it doesn’t happen overnight,” says Dr. Molosky. “It may be a few months or more before your period comes back but stick with your doctor’s plan and give your body time to heal.”
Unfortunately, these changes are sometimes easier said than done. The culture tells athletes, especially females, that thinner is better. And if you’re dealing with an eating disorder, specialized care is key.
“You can’t simply tell someone to ‘eat more’ if they have an eating disorder or body dysmorphia,” says Dr. Molosky. “We need to address underlying mental health needs to achieve physical health.”
You Can Train Hard and Keep Your Period
It’s possible to make the team, improve your fitness level or run a marathon without experiencing RED-S. In fact, it should be considered the norm to train hard and have regular periods.
“Your body is always working toward a balance, but it needs the right amount of calories to get there,” says Dr. Molosky. “Losing your period isn’t healthy—it’s your body trying to tell you something is wrong. Give it the calories and carbs it needs, and you’ll be able to reach your fitness goals in a healthy way.”
Reviewed by Juliana Molosky, M.D., sports medicine physician at Henry Ford Center for Athletic Medicine.
