Is it normal to miss a period?

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I've noticed that since I've started training more, my period has stopped (I am a runner). Is that normal?

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I found that when I was marathon training that my period definitely reduced from the heaviness that it normally was at. When I finished that training cycle it did go back to normal. So it didn't disappear altogether but it definitely changed.

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I am not an expert but have done quite a bit of reading on female athlete health and my understanding is that it is not normal to not have a period. However, there are many reasons one might lose a period so it’s definitely worth finding out why.

Dr. Stacy Sims has some good resources around female physiology.