When I ceased contraception to try to conceive, aged 30, I realised that my high running load was probably impacting my ability to ovulate and menstruate. My doctors didn't acknowledge it because I was still within the 'normal' BMI category and my hormones were borderline within range. Then I read 'No period, now what?' and stopped running, did some gentle walking, ate more, gained a little weight. It took four months of this for my period to return but it was so irregular. After a further eight months of irregular cycles, I was fortunate to become pregnant. It was an unexpectedly long year trying to conceive, given I thought I was 'healthy'. I'm now more moderate in my exercise and feel better for it. Thank you for bringing light to this.