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12 April 2024

Fertility and over-exercising – is your gym habit hindering your natural fertility? We ask our expert, Dr Andrew Murray


12 April 2024
Updates

Hi Dr Murray, thanks for having a chat! So, we hear a lot about women not exercising enough being detrimental to fertility – but what about the dangers of over exercising? Is this a thing?!

So when it comes to exercise and fertility, it’s quite similar to a lot of things and that all things in moderation are probably fine. But it’s when you go to the extremes of excessive exercise – that’s not a good thing.

But there are some specific things about exercise that are probably worth highlighting. Let’s talk about the extreme, real intense over exercising. One of the reasons that women will sometimes come to see me is because their periods have disappeared altogether. What’s going on at a physiological level is it’s almost like the body’s been tricked into thinking, ‘are we in a famine here? This is not a good time to reproduce, because all the calories are being diverted into recovery and energy.’ The brain shuts down the reproductive hormones that it sends to the ovaries – it says ‘right, well hang fire, ovaries don’t release any eggs because there’s no food around at the moment, this is a bad time to reproduce.’

The medical term for this is called Amenorrah, which just means no periods. Now, having no periods in and of itself doesn’t mean your eggs are damaged- they can just be sitting there waiting for the next call-up.

Does low estrogen have anything to do with this?

One of the other important jobs the ovaries have is to produce the hormone estrogen, and an estrogen such an important hormone for women because it’s what helps provide the elasticity to the vagina and helps keep the skin supple. If you have low levels of estrogen, your brain doesn’t function as well.

Now, if we turn that back around to women who are trying to conceive, the concern is if your periods are absent, it also means your ovaries are very shut down. You’re not ovulating. But, the positive thing goes it’s all completely reversible by reducing training levels, and ensure that the lean body mass is not so low – typically we talk about the magic standard is no less than 50 kilos. There’s no one-size-fits-all with us, but above 50 kilos for most women is going to be the sort of minimum weight we would want people to be to expect normal ovarian function.

So are we just talking about professional athletes here, or is this something that can affect everyday women – sometimes without them realising?

There is a level down from what I’ve just described tat I think sometimes needs to be reviewed. So these would be women who are, say, going to the gym five to six times a week. That’s doing several rounds of stuff like high intensity training. There’s been a couple of studies now that show that this can be harmful – it’s counter intuitive, I know – you would think that someone who’s motivated and doing that level of training would have better fertility outcomes because they’re not the ‘overweight ‘patient that we often think of as having fertility problems. But the fact is that gym junkies tend to have lower pregnancy rates in IVF programs.

It sounds like it’s quite hard to get to the sweet spot – are we just talking high-intensity stuff here?

The reason why we think that’s the case is that with high intensity training at that level, you’re getting literally no break of significance and you’ve got constant and chronic inflammation going on in the body. That’s how the training is working – you’re stressing the muscles and the tendons. And you know, we’ve all experienced that soreness and slight heat when you’ve particularly done a new exercise. Well, that’s inflammation, which is what ultimately is repaired by muscles and what makes you stronger.

But if it’s done consistently, that level of inflammation is circulating around the entire body, and there is some thought that it may have an inhibitory effect on the embryos. Again, it comes back to that age-old advice – all good things in moderation. If I’m seeing someone who’s exercising six times a week or more, I’ll say to them, look, let’s mix it up a bit – instead of six high intensity training sessions a week, why don’t you swap a couple of those out for a long walk in the bush, maybe do some meditation or some yoga or something that’s a little less full-on.

So, it’s a case of keeping inflammation low, and everything else in moderation?

Yeah – this is why diets that are rich in antioxidants are so useful and powerful because the goodies in antioxidants help repair the damage that is caused by inflammation – when I say that, I don’t mean go out and buy a bunch of supplements. I think a good healthy diet with plenty of green leafy vegetables – the Mediterranean style diet is one that I think is a very good one for this kind of thing and for fertility in general.

This story was brought to you with the support of Fertility Associates and as part of our ongoing partnership – click here for our previous instalments.

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The Biological Clock

This tool indicates:

  • Natural conception per month if you have no fertility issues
  • IVF success rate at the same age
  • When to seek help after months of unsuccessful attempts

If you are concerned at any stage – we recommend booking a doctor appointment or a free nurse consultation. The sooner you make a plan the better your chances in the long term.

When to seek advice early

  • If you have polycystic ovaries, endometriosis, or have been through a cancer diagnosis; we recommend you get in touch quickly so we can talk you through all your options and give you the greatest possible chance of success.
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Body Mass Index calculator

Being overweight or underweight can reduce fertility, so it is important to keep your body weight within the normal healthy range.

Body Mass Index (BMI) is an indication of your body weight and can be calculated by dividing weight by height. You should aim for a BMI of between 20 and 25, as this will optimise your chances of conception.

Woman’s BMI below 19

Even in these modern times, nature knows best. If a woman's BMI falls below 19, the body senses famine and ovulation is switched off to prevent the risk of having a baby with malnutrition. Excessive exercise can reduce body fat and increase muscle mass to a point where periods cease for the same reason. Risk of miscarriage is also increased in women with a low BMI.

Being underweight

If a woman's BMI falls below 19, the body senses famine and ovulation is switched off to prevent the risk of having a baby with malnutrition. Excessive exercise can reduce body fat and increase muscle mass to a point where periods cease for the same reason. Risk of miscarriage is also increased in women with a low BMI.

BMI’s greater than 30

This can reduce fertility by 50%. Pregnancy for women with a 30+ BMI is often associated with problems such as maternal diabetes, high blood pressure, big babies and increased risk of caesarean section.

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