effect of exercise on female fertility?

[didwedotherightthing]

I'm re-reading a book by fertility expert Alice Domar. In it she makes a brief reference to the fact that for some women, regular exercise causing a heartbeat of 110bpm or more can reduce fertility. Has anyone heard the same, seen research on this or have a personal experience that seems to fit this.
I'm a bit concerned as I took up running as a coping mechanism to deal with infertility and ran half marathons - only 1 a year with associated training - to fundraise when TTC DC1 who ended up being conceived via IVF.
We're TTC again and after 2 miscarriages since October I've started running more regularly and hope to run a 10k or half mara again this year. Bad idea?

bump

Yes I've heard of it... I have a diagnosis of hypothalamic amenorrhea. Consultant said I was over exercising - I think it was more of a case of not eating enough, exercising and low body fat. Have reduced exercise and eaten more (including less sugar and much more protein) and AF returned after a 381 day cycle (after stoping the pill). There's a whole section for HA on the Fertile Thoights forum - well worth a read.

Thankmoomin. The book didn't mention ammenorhea specifically though and I have a regular cycle and ovulate each month. I'll look into it some more.

I have heard this too. I think there was an article about it recently when Kate got pregnant . It claimed exercise was good but it should be gentle, not raise heart rate too much and not be for long periods as it puts stress on the body .

Hi didwedo

I don't know the science behind it but I can talk from my experience.

Last year for a period of 5 months I was running a lot, over 150kms a month/4-5 hours a week. During this time my period length doubled! From around 33-35 days average I then had three cycles of 60-70+ days!! After the mammoth cycles I still have 3 more long cycles at 40+ days!!

I did loose a bit of weight (have always been around BMI around 20, maybe dropped to 19?) but I think it was more related to the exercise than anything else.

18 months later, still TTC and I have cut out all running. I now walk, swim, play tennis and complain about my flabby fat.

Hopefully it'll all be worth it!!

x

heartbeat over 110 is nothing special, sheesh!

It's when you workout so hard that you lose periods for extended periods (like many months over years) that I could make sense of this, because you're literally changing the chemistry of your body. Heartbeats near 110 are not going to make a person lose menstrual cycles.

I've nattered with other moms of many & who kept jogging until 39-40 weeks. We're not truly athletic at all, either. I should think my HB was over 170 when I was jogging & I'm a pretty slow runner.

Yes there is always the story of Paula Radcliffe being just preggers when running the marathon so she would have conceived after/during months of hard training.

But I guess when there are already infertility issues might cause problems.

On my first Fertility Clinic appointment the consultant asked me whether I ran long distances (I wasn't anymore by that stage).

I guess it affects everyone differently, but personally my opinion is that it would have an affect on someone who was already suffering from fertility issues. I love running and if/when I do finally get pregnant I would love to run during my pregnancy and always thought I would... but my opinions on the matter have changed and now personally I wouldn't, and wouldn't recommend any "hectic" exercise to anyone who is pregnant. Maybe I have become paranoid though!