MyMT™ Blog

The Evolutionary Origin and Significance of Menopause.

With the possible exception of pilot whales, no mammals studied to date are known to commonly exhibit the cessation of their reproductive capacity as they get older. Except of course, for human females.

I didn’t know that. Did you? 

Over the lockdown period here in New Zealand, I’ve been using my time not being able to travel to catch-up on articles of interest – many plonked in piles in my study awaiting that precious commodity that we’ve all complained at some stage that we don’t have enough of – more time! But now there was time.  And in my pile of articles was one that I hadn’t read before with the simple but intriguing title – ‘The evolutionary origin and significance of menopause.’  (Pollycove et al, 2011). 

I want to share with you what’s in it. Because for many of you, it might just help you make sense of your symptoms as you navigate this life-stage, which for millions of women around the world, throws them into some emotional and physical chaos. It was the same for myself as well. 

But here’s the thing. Menopause is relatively unique to us as a species. And 100 years ago, it might not have been a problem, simply because we didn’t live very long. 

Menopause heralds in our biological ageing. From a physiological perspective, we are finishing our reproductive capability and in natural menopause (as opposed to surgical menopause), our ovaries are going into decline. As such, we reduce substantially our ability to make oestrogen. In most western countries, the average age of menopause begins around our mid-40’s (called peri-menopause) and ends when we haven’t had a period for a year or more (called post-menopause). In many societies, women reach post-menopause around their mid-50’s. 

Several theories have been proposed to explain why menopause might have evolved and efforts to understand this biological event have engaged anthropologists and evolutionary biologists for decades. Many of these theories are based on aspects of the human life history whereby Menopause is seen not as a disease, but as a survival advantage.

One of these theories is known as the ‘Adaptive Theory’. This theory views ovarian failure and menopause in human females as favouring survival of their daughters.

Anthropologists believe that because human babies are incapable of moving around on their own soon after being born, and human babies need to be fed and nourished, then menopause has become a survival adaptation. Post-reproductive grandmothers who don’t reproduce any more themselves, can therefore, assist their adult daughters. That’s why this theory is also known as the ‘Grandmother Theory’.  In the grandmother hypothesis, females can gain benefits from stopping reproduction long before they die by helping to care for their existing children (or grandchildren) instead of producing more, which helps their descendants to survive. Alternatively, benefits can come from taking over the childcare duties of their grandchildren, meaning their children are able to have more offspring than they could otherwise. Of course, both their children and grandchildren will carry their genes. 

‘Natural selection would favour females who become infertile many years before death if offspring require exceptional duration and intensity of parental care, as is the case wiht humans’ suggests the authors (Pollycove et al. 2011, p. 2).

Then there is the theory that child-bearing at older ages is relatively risky. There may be little advantage for an older mother in running the increased risk of a further pregnancy when existing offspring depend critically on her survival. I do tend to agree with this one. Bringing up very young children in our 50’s and trying to cope with not sleeping in menopause doesn’t even bear thinking about! 

Why menopause may have evolved has been debated for decades. But researchers do tend to agree on the fact that this stage of life confers some advantages toward survival. Not only for older women, but for daughters and grand-children. They also agree on something else to do with menopause. 

The stage of life when oestrogen production is reduced, accelerates ageing and advances disease risks due to an increase in inflammatory changes over time. 

This is the conclusion I came to as I did my own studies on women’s health as they age. Menopause is the gateway to changes in the body that accelerate ageing. It’s why I have placed the MyMT™ 12 week programmes within ageing research. Or should I say, ‘healthy ageing research’! Not all ageing is healthy. You’ve heard me say in my blogs before that ageing itself is inflammatory (there is a new term called ‘inflammaging’ coined by ageing researchers).

Inflammation in the body makes our symptoms worse. 

The term ‘inflammaging’ refers to chronic, low-grade inflammation that characterises ageing. And as I keep reminding women, even though we feel young perhaps compared to our mother’s generation at the same age, we must also remember that inside our body, our cells are ageing. Furthermore, when we aren’t sleeping, we aren’t healing from all the stress that we are under.

And I don’t just mean emotional stress. I often talk about those women doing lots of high-intensity exercise most days of the week (as I used to as well), because this can increase physical or oxidative stress inside our cells and tissues when we aren’t sleeping well. Like over-trained athletes, we then fail to heal properly when we don’t sleep. Inflammation builds up and this begins to affect several tissues and organs, including the gut microbiota. This is why I developed a brand new module for you during lockdown, called ‘Restore Your Grateful Gut in Menopause’ – you can read about it HERE. 

Reducing the effects of our biological ‘inflammaging’ is important to our ongoing health. It’s what I talk about in the MyMT programmes as Helene from Edinburgh discovered! 

Menopause is the biological gateway to our ageing. As such there are numerous changes that occur around the body that not only accelerates ageing but increases the build-up of inflammation. When inflammation is higher than normal, our chronic stress hormone called cortisol, remains higher than it should too. 

When cortisol is high in the body, this causes even more inflammation. And I talk about why this is, in my ONLINE Masterclass on Menopause webinar which I recorded for you in lockdown. Whilst it’s 2 hours long, you can pause it anytime you like. In there, you’ll hear me talk about the slide below. I never knew the importance of understanding the role cortisol has with our sleep hormone called melatonin, until I undertook my women’s healthy ageing studies and began to put the menopause symptom jigsaw together.

If cortisol is high at night, then it interferes with the production and secretion of melatonin. Without enough melatonin being produced during menopause, you toss and turn all night or as many of you have already discovered, you’re awake and watching the clock around 3am. That used to be me as well. 

There’s also another anomaly that scientists are learning about menopause and this is, that we weren’t supposed to live so long. In the pre-agriculture, hunter-gatherer period, there was minimal life-expectancy after menopause – around 65 yrs or less.  Hence, when the life expectancy of women was only 65 years, women didn’t have to concern themselves with their ageing. 

Today however, we do have to concern ourselves with our ageing.

Many of us have watched our mother’s generation age with all sorts of ailments and functional disabilities. I remember my own mother going on “heart pills’ probably in her late-50’s or early 60’s and complaining about knees and ankles that were continually swollen and sore. A knee replacement helped, but her activity slowed and the weight went on and her health was never the same. 

Improvements in medicine, public health, socio-economic conditions and nutrition has increased our life-expectancy. In the 21st Century, the largest population expansion in women living in the United States is in those over 65 years. This means that a third of a woman’s life will be in her postmenopausal period. That’s why it is essential that we all understand how to manage this period of our lives, make some adjustments to our lifestyle in line with the changes that arrive and be able to enjoy optimum health. At 62 years old, Bev in the photo below, now looks and feels amazing. I’m so pleased she came to my seminar in Christchurch, New Zealand a couple of years ago and joined me on the MyMT Circuit Breaker programme. 

Menopause is derived from the Latin words “meno” which means ‘months’ and “pausia” which means ‘halt’ respectively. But whilst Menopause marks the end of a woman’s period of natural fertility, it doesn’t mean that we can’t feel healthy and happy as we age. 

But what this requires is that we turn around our symptoms, especially if we aren’t sleeping or if we are experiencing worsening hot flushes, weight gain, depression and joint pain that is preventing us from staying active.  Paleontologists who study the evolution of menopause report that female hunter-gatherers remain generally active through their late menopause years and are therefore, least likely to be bothered by menopause symptoms. This was evidenced by data on sleep disorders in women from less developed nations as compared with sedentary women in post-industrial countries (Pollycove et al, 2012). Furthermore, in more recent research, studies into the habits and physical activity patterns of women from the Hadza hunter-gatherer tribe in Africa also found that menopause symptoms (measured as hot flushes) were low and this was partly attributed to the fact that on average, women walked 6km a day. I talk about this research in my 12 week programmes. It’s an important starting point for women to know ‘how much exercise is enough?’! 

For millions of women around the world, their menopause transition throws them into health and symptom chaos. But it doesn’t have to be like this at all. I used to feel so frustrated and despondent until I began to research menopause. When I discovered that it really is the biological gateway to our ageing, and that as we age, we need to understand how to manage and/or reduce inflammation, I explored the women’s healthy ageing research to find out how. The result of this are two different programmes which I called My Menopause Transformation. I hope that one day you might join me and just a reminder that the price has changed to fit in with our changing world at the moment and there is NZ$100 off the price, making it NZ$199 for the 12 week programme for a limited time only. 

All programmes are ONLINE and you listen to my videos, webinars and other information in your private learning hub in my member area. There are 7 modules of around 50 minutes each, and these are opened up for you each fortnight so you get a chance to listen, learn and then put into action the strategies I’ve researched for you. As well, I have a private coaching community and you can always email me with  your questions too. Women tell me every day that what they learn about menopause and what I tell them to put into action is simply ‘life-changing’. If you come on board, then please use the promo code ATHOME20 in any Buy Now button. I want the programme to be ‘life-changing’ for you as well. 

My video is below explaining how the programmes might help you and how they work. Have a listen when you get time. 

Dr Wendy Sweet (PhD) My Menopause Transformation Founder/ Member: Australasian Society of Lifestyle Medicine 

 

References: 

Arbuckle, K. (2016). Why do women go through menopause? Science offers new solution to old puzzle. The Conversation. 

Austad S. (1994). Menopause: an evolutionary perspective. Exp Gerontol. 29(3-4):255‐263. doi:10.1016/0531-5565(94)90005-1

Pollycove R, Naftolin F, Simon JA. The evolutionary origin and significance of menopause. Menopause. 2011;18(3):336‐342. doi:10.1097/gme.0b013e3181ed957a

Shanley D., Kirkwood T. (2001). Evolution of the human menopause. Bioessays. 23(3):282‐287. doi:10.1002/1521-1878(200103)23:3<282::AID-BIES1038>3.0.CO;2-9

“If you have ever wondered if there was a clear easy plan to follow to sleep all night, reduce hot flushes and prevent or reduce your weight gain during menopause, then ‘welcome’ – you’re in the right place now.”

Discover how either of my two Menopause Transformation programmes might help you too or take my Symptoms Quiz below… 

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