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  • Writer's pictureErin White

What is Relative Energy Deficiency in Sport (RED-S) and How Does it Affect Fertility??

I am SO excited that my CEU (continuing education course) on pre and postnatal care has officially started! I know I’m a pediatric physical therapist, but the topic of fertility and pre/postnatal care has become of increase interest to me ever since our miscarriage last May, and obviously being 23 weeks pregnant now! I’ve been reading tons of research over the last year on this and was very excited when I saw this course because I know it’ll help so many people and not just me!

This was a topic that was address in my first week material and I wanted to share it with you all because it was a newer term for me.

So what is Relative Energy Deficiency in Sport (RED-S)? It’s an often unrecognized disorder that can include low energy availability (inadequate caloric intake), amenorrhea (lack of menstrual periods), with or without disordered eating, and low bone mineral density. With RED-S, disordered eating can include intentional or non-intentional under-consumption of calories. This can be from both poor eating habits and partaking in too intense of exercise.

For people who have normal menstrual cycles, if the body perceives a gap between energy expenditure and energy intake it will lower the estrogen levels in the body and therefore cause menstrual cycles to stop. This is why some young athletes have a hard time regulating their cycles in early adolescence.

So who’s at a higher risk for developing RED-S? Any female who is physically active is at risk. Obviously, the more rigorous the activity, the higher the chances. Often this is associated with very lean females, but this is not always the case.

How can RED-S affect performance? The lower energy available causes a slower and weakened overall output with physical activity. No matter what you’re doing physically, if your muscles lack sufficient fuel then your performance will be impaired. Loss of menstrual periods (amenorrhea) can cause bone loss due to the drop in estrogen production. This loss of bone mineral density is crucial to anyone, but especially highly active females as it can set them up for injury.

How can RED-S affect fertility? When your body doesn’t have enough energy to perform daily activities it won’t have enough energy to preserve reproduction function either. On average, it can take 9+ months to get the body back into a healthy weight for ovulation. When a females overall BMI is too low, her body is unable to produce the right hormones for ovulation and therefore conception.

How can I know if I have RED-S? Although this is often thought about in terms of young female athletes or those engaging in highly vigorous training, it can affect anyone engaging in physical activity. Consider this scenario, a new mom or working mom who has been consistent in her program and is getting good results. She starts to lose weight, feels great again, and is getting tons of compliments. So she starts eating less and exercising even harder. She’s also not getting enough sleep (because hello baby). She starts to notice period irregularities, exhaustion even after a full nights sleep, and needing more and more caffeine. This mama has RED-S.

How do you treat RED-S? The treatment protocol for this is reversing the underlying cause – low energy availability. This is done my increasing dietary intake (of good, nourishing foods) and decreasing the energy expenditure through limiting intensity and quantity of exercise.

Do you feel like you might have fertility issues that could be cause by RED-S? Please contact your OBGYN with these concerns and start discussing a plan today! Being healthy doesn’t mean being underweight and having low energy!



Hi, thanks for stopping by!

I am a wife to my amazing husband Zach and a momma to an angel baby and now a beautiful baby boy. I am an anxiety warrior, a follower of Christ, and a devoted wife, mother, daughter, friend, and sister.

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