Life Expectancy is Sexist

On average, women live 7.5 years longer than men. The reason for this? Well, there are hundreds of potential culprits most of which are still unknown. Yet, there are a few hypothesis medical researchers have given particular attention to.

The Female Kingdom.

Females outliving their male counterparts has been observed throughout the animal kingdom, some epic Darwinian design to keep populations growing. The lives of females from all different species seems to correlate with the time their offspring remain dependent. Although, judging by the amount of adults still living with their parents, in our current human race this seems to be hugely variable. It does however provide us with an evolutionary basis for longevity, the slower we age, the more time we have to reproduce.

 

Old women by Edwin M Escobar via www.flickr.com licensed by creative commons.
Old women by Edwin M Escobar via www.flickr.com licensed by creative commons.

Check out this study to see the correlation of fecundity with age.

Perls, T, Alpert, L, & Fretts, R 1997, ‘Middle-aged mothers live longer’, Nature,389, 6647, p. 133, MEDLINE, EBSCOhost, viewed 26 October 2014.

 

Getting Big.

So although many men may look at themselves in the gym mirror a little too much these days, there’s actually a biological reason for a self-absorbance in size.  Having an abundance of males was never key to a sustainable and increasing population. From an evolutionary perspective men have always had to be the largest and strongest to compete for a “place”. Even if being bigger meant sacrificing the perpetuation of other organs. What did living long matter if you weren’t going to be successful in furthering your genetic line?

From day one boys render themselves vulnerable to onset of disease and early death. A male fetus exposed to adverse conditions in the womb (such as famine) will develop renal, cardiac, bone and pancreatic problems more readily than a female.

Why is this? Men, as we all know, want to ‘get big’. Their adaption to physiological challenges could be described as negligible at best (as we witness with the ‘man-flu’) and refuse to trade in size and strength for survival.

In non-optimal intrauterine conditions boys are more likely to be born with undesirable problems such as smaller cardiomyocyte number (less heart cells), glucose intolerance (predisposing them to diabetes 2) and decreased nephron number (smaller kidneys. In the pressure of natural selection the male species seem to put scarce energy supplies towards growing and reproducing, clearly not longevity.

Fast forward a few years and another theory emerges. This one I first heard from my German grandma, but it goes by the lifestyle men lead. My grandma, described it as “lebensmüde”. Literally translated to “tiredness of life”. This is used to describe someone who does something- “and I use this word seriously; stupid” (CNN Reza Aslan interview). The person is so bored with life, they have to do ridiculous things to enjoy it. I think the evidence for that is well represented in our new generation of jersey-shore youth resembling ken-dolls-dipped-in-tea-and-covered-in-biro.

While I’d argue my grandmas description is slightly exaggerated the dicey type of activities men part-take in during younger years is a major contributor to their heightened risk of premature death. Unhealthy behaviors such as heavy drinking, smoking, employment in hazardous occupations, risk taking in recreation and driving, and aggressiveness all contribute to higher rates of cancer and homicide.

You could argue a women could behave the same way, BUT there is one major component speaking for their heightened physical irrationality, testosterone. Which becomes relatively apparent in the conspicuous spike in sex-mortality ratio at puberty, along with the need to re-package themselves as “bi-ceps-on-legs”.

The Heart.

Heart by nova031 via www.flickr.com licensed by creative commons
Heart by nova031 via www.flickr.com licensed by creative commons

Cardiovascular disease is a major killer in the Western world today and the primary reason for a gender gap in mortality. It gets men earlier, 7-10 years in fact and 5 times more likely to develop in the first place. It is assumed the exposure to endogenous estrogens early in life acts as a sort of protective mechanism against arthrosclerosis (the stiffening of our arteries) as the prevalence of cardio related problems arise post-menopause. So all those hormonal-linked-emotional-breakdowns, worth it ladies.

Obesity.

Yes, okay, women are generally more obese then men, which may argue against a “healthier life style adoption” theory. However, we do tend to deal with obesity better. In fact, we are very good at spreading adipose tissue evenly across our bodies. In contrast men tend to develop that lovely “beer belly” physic that we all respect in terms of college drinking aptitude.

Rotund by Rick Bolin via www.flickr.com licensed by creative commons
Rotund by Rick Bolin via www.flickr.com licensed by creative commons

Unfortunately, this “central obesity” is highly correlated to heart disease and stroke. Somehow, even the female fat distribution has managed to better adapt to survival.

The Female Paradox.

There are gender specific aspects that contribute to life expectancy on both sides. In younger years women shed uterine lining every month, loosing a lot of blood and having an overall lower iron concentration. Iron is need to form free oxygen radicals, therefore women have less and our cells are broken down less.

Eostrogens, leading to this process and a calmer lifestyle are an acting ward against many diseases, yet has its downfalls. A, when going into menopause. Although it can be argued that menopause bestows a type of biological advantage by preventing us from the physiological stress of pregnancy in old-age.

And B, we are more prone to chronic nonfatal conditions such as arthrius, oesteoporosis and autoimmune disorders; reducing quality of life. It seems men die faster and younger, a blessing in disguise?

In truth aging and the difficulties that come with it is a build up of things. A Jenga tower waiting for the last block to be pulled out; where women are born with slightly more blocks to begin with. It is hoped that one day scientific research can help isolate a true reason for this disparity but as for today anywhere you go in the world the story is always the same: women live longer than men.