breakupIf you’ve been reading these Hormonology Tips for awhile, then it’s pretty clear I love reporting on studies that show how our hormone cycle impacts our behavior and health.

However, I’m also a big fan of learning about WHY our hormones do these things to us.

While our many hormonal effects may seem arbitrary, unnecessary and, let’s face it, sometimes downright mean at first, researchers believe there are practical reasons our body evolved to have hormones impact us the way they do–and they’ve got lots of theories about them.

For instance, researchers speculate that high estrogen in Week 2 of our cycle makes us distrustful of attractive women because we subconsciously view them as competitors for mates. And they believe rising progesterone makes us gobble up more high-calorie foods in Week 3 of our cycle because this hormone wants us to start eating for two in case we got pregnant during ovulation.

Well, there’s a theory that’s being put forth about the reason we gals evolved to experience premenstrual syndrome (PMS) in a new article in the journal Evolutionary Applications. I’ll summarize it, but you can read the full article for yourself here.

Okay, so are you ready to hear the possible reason we gals get PMS?

It’s to advance the human race.

Hand to my heart, that’s what the article suggests.

Now, I know what you’re thinking: Certainly, there must be better ways to advance the human race that don’t involve so much teeth-gnashing and bingeing on cupcakes.

Well, as frustrating as PMS could be for us in modern times, in the early days of humankind, the moodiness, depression and irritability women encountered when estrogen plunged premenstrually–proving they weren’t pregnant–could have been an efficient way to chase off an infertile mate and find a new, fertile mate who could help them conceive, according to the article’s author, Michael R. Gillings, Ph.D., a professor of molecular evolution at Macquarie University in Austrialia.

This way, women would have more babies, ensuring the survival of the human race–which, long before the advent of careers, theme parks and luxury sports cars, was among the top motivating forces of humankind.

Gillings supports his hypothesis by citing studies that show we gals tend to focus our premenstrual negativity at current partners (suggesting break-ups are more likely to occur as a result during this phase of our cycle), yet we still have a high libido on these days (suggesting that women of yore were still interested in pairing up–just not with a guy who couldn’t help them populate the world).

Gillings goes on to point out that, as horrible as PMS is, ancient gals may not have actually spent a lot of time battling it. That’s because, between successive pregnancies, breastfeeding and ditching infertile mates through the evidently very efficient PMS Ray Gun method, early women averaged only two or so menstrual cycles per year.

Contrast that with today when many of us go through an average of 12 cycles per year thanks to the control those of us in advanced societies have over our reproductive life–giving us plenty of opportunity to experience repeated PMS in all its fire-breathing glory.

If you read the full study, you’ll see that Gillings goes on to suggest that, since modern gals no longer need PMS to cast off seedless gents, we can use this information as an excuse to avoid PMS by skipping the whole menstrual cycle thing altogether, for instance, by using continuous contraception. However, I’m not a fan of opting out of your natural monthly cycle as a first-line of defense against PMS.

Aside from control over our reproductive life, modern woman has another thing going for her: Medical research that shows how to reduce bothersome premenstrual symptoms–and even nix them altogether–through diet, exercise, supplements and other easy lifestyle changes.

You can take a look at a bunch of PMS-busting studies I’ve reported on here.

So, what do you think: Does this theory seem to make sense? Or do you think there’s another plausible reason behind PMS? 

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