Why women live longer than men

Nov 01, 2010 by Lin Edwards report

(PhysOrg.com) -- On average, women live five or six years longer than men. There are six 85-year-old women to four men of the same age, and by the age of 100 the ratio is greater than two to one. Many hypotheses have been proposed to explain the greater longevity, but there is growing evidence for the disposable soma theory, which says males are genetically more disposable than females.

A common idea is that men die younger because they have more stressful working lives than women, but if this were true the gender gap should be decreasing rapidly as women’s work comes to more closely resemble that of men. It can also be said women now have the additional stress of working outside the home on top of the stress of working inside the home, and yet there is little evidence the longevity gap is reducing by much.

Another hypothesis is that women live longer because they are less likely than men to adopt unhealthy habits such as smoking or drinking to excess, and more likely to eat well. The problem with this hypothesis is that, while do tend to live longer than men, they are generally less healthy in their old age than men of the same age. Another problem with this idea is that the females of most other species also live longer than males.

It is a generally accepted theory that our bodies age because of a gradual accumulation of tiny faults or damage to cells or cellular components such as protein or DNA. The degenerative build-up occurs because the body’s regenerative processes are not quite perfect, and some of the damage remains unrepaired.

Professor Thomas Kirkwood, director of the Institute for Ageing and Health at Newcastle in England, first suggested in 1977 our bodies do not repair themselves as well as they could because natural selection favored the growth and reproduction phases of life over older age, in essence viewing the body as a short-term vehicle for passing on the genes to the next generation and not worth the energy investment in keeping itself going for the long term. This may have been especially true in the hunter-gatherer period when the risk of accidental death was so great. Professor Kirkwood called this the disposable soma theory (soma being Greek for body). In an article to be published this month in Scientific American, Kirkwood extends his theory to explain the longevity gap.

Kirkwood’s laboratory research has shown that long-lived animals have more efficient maintenance and repair systems than short-lived animals, and that long-lived animals tend to be larger, more intelligent, or have some adaptation (such as wings) that allows them to escape danger. For these animals, it seems the body is somewhat less disposable and investing energy into maintenance pays off. This leads to the idea that males have shorter lives than females in most species because they are genetically more disposable.

Laboratory studies have also shown cells in female rodents repair damage better than in males, but this difference is eliminated if the ovaries are surgically removed. It is also known that castrated male animals tend to live longer than intact animals. According to Kirkwood there is also evidence from an institution for the mentally disturbed in Kansas, where castration of male inmates was once a common practice, that castrated lived an average of 14 years longer than uncastrated inmates.

Further evidence for Kirkwood’s theory comes from research in Japan in which scientists created "super female" mice from genetic material from two females, with no genetic material from a male. These mice lived a third longer than ordinary female mice.

Professor Kirkwood said it is important for the species for females to have healthy bodies, since they bear and nurture the next generation, whereas the male reproductive role is shorter-term and less related to his good health. So for females the driver for successful mating and rearing of offspring is a healthy body, leading to a tendency to live longer, while the driver for mating in males is not related to longevity. In fact, high testosterone levels (related to high fertility) tend to shorten the lifespan.

Professor Kirkwood said while it's "difficult to say things with absolute assurance" he is confident his theory of males being more "disposable" than females is the underlying biological explanation for the greater longevity of females.

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User comments : 28

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Bob_Kob
3.8 / 5 (9) Nov 01, 2010
What about the theory that men take more risks to get women and thus end up dying because of stupid mistakes?
random
3.8 / 5 (4) Nov 01, 2010
That doesn't account for female rodents healing themselves better than the males.
Lexey_Mamoru
4.8 / 5 (4) Nov 01, 2010
Bob_Kob, there are a lot of such males, but also not very small community of lazy men, who do nothing...
Kedas
2 / 5 (2) Nov 01, 2010
Not sure if an survival difference at such an old age actually matters for the common good.

It could be that does old men are tired of listening to that old women next to them. ;-)
mysticfree
5 / 5 (8) Nov 01, 2010
In my own experience, it is rare that I heard a woman say those famous last words, "Hey y'all! Watch this!"
kevinrtrs
1.5 / 5 (8) Nov 01, 2010
Professor Kirkwood said while its ..difficult to say things with absolute assurance.. he is confident his theory of males being more ..disposable.. than females is the underlying biological explanation for the greater longevity of females


So what he's really saying is that he firmly believes in his own theory, unproven as yet and highly debatable. It's just a matter of time before it's proven. Maybe in the next 10 million years.
Just right now, nobody knows why women live longer than men.

epsi00
not rated yet Nov 01, 2010
well at least now we know the secret to eternal life: castration at an early age, maybe in the womb!
El_Nose
5 / 5 (1) Nov 01, 2010
@mysticfree

Sir, it is my opinion that you go to the wrong bars. ;-)
CarolinaScotsman
5 / 5 (2) Nov 01, 2010
Okay, pure speculation here, but could it be that because of our evolutionarial role as hunters (and to a lesser extent as soldiers/warriors), men have a more sensitive fight or flight response? As a result, could we then be exposed more frequently and to greater volumes of stress causing (and life span reducing) hormones? After years of more intense exposure, could this measurably shorten our life spans?
droid001
3 / 5 (2) Nov 01, 2010
man eats more than women,thus,greater oxidation
krundoloss
4.2 / 5 (5) Nov 01, 2010
Sounds like it may be related to horomones, huh! Think about it, castrated males live longer, and female rodents heal better until thier ovaries are removed. Hmm, could it be that Testosterone = live hard, die young and Estrogen = Live soft, live long. I think we should be paying closer attention to the effects of adult horomones on aging. Just how testosterone levels influence balding in men, perhaps it can trigger other forms of body degradation. Doesnt Estrogen loss lead to bone loss in women, too.
Royale
not rated yet Nov 01, 2010
how does Testosterone affect balding? I'm asking because my Dad and his Dad kept their hair but his brothers lost it, I wonder where genetic effects drop off and where hormone levels pick up..
CarolinaScotsman
1 / 5 (2) Nov 01, 2010
Sounds like it may be related to horomones, huh! ... Just how testosterone levels influence balding in men, perhaps it can trigger other forms of body degradation. Doesnt Estrogen loss lead to bone loss in women, too.


Testosterone causes baldness? Urban Myth http://www.sexlov...acts.htm
Husky
not rated yet Nov 02, 2010
in Blade Runner the cloned people have superior physical abillities at the expense of duing early
Skeptic_Heretic
5 / 5 (1) Nov 02, 2010
Testosterone causes baldness? Urban Myth http://www.sexlov...acts.htm
Testosterone won't give you baldness if it isn't already in the cards for you, however, increasing testosterone levels will provide increases in genetic expression of masculine traits, including baldness. It will also increase the aging process. If you look at atheletes who use they tend to suffer from diseases 10-20 years earlier than the average. ie: Pro wrestlers getting cancers and heart difficulties, runners dropping dead of strokes, advanced calcification of bones, etc.

Testosterone promotes growth, estrogen doesn't. Probably because testosterone increases the cortizon production process, and cortizone is a genetic regulator involved in cellular apoptosis.
CarolinaScotsman
5 / 5 (1) Nov 02, 2010
It will also increase the aging process. If you look at atheletes who use they tend to suffer from diseases 10-20 years earlier than the average. ie: Pro wrestlers getting cancers and heart difficulties, runners dropping dead of strokes, advanced calcification of bones, etc.

Athletes (who use anything), by far, use steroids, an artificial hormone that is related to testosterone but not the same. The effects you mention are for steroids, not natural testosterone.
trekgeek1
4 / 5 (1) Nov 02, 2010
"castrated male animals tend to live longer than intact animals."

Oooohhhh.......... tough choice. Actually, never mind, what the hell would I do with that extra 14 years without the little guy around? Especially if there's a 6/4 female to male ratio!
Royale
not rated yet Nov 03, 2010
trek. You do realize that castration is the removal of testes right? You'd still have "the little guy around" you wouldn't, however, have his two friends.
Skeptic_Heretic
5 / 5 (2) Nov 03, 2010
Athletes (who use anything), by far, use steroids, an artificial hormone that is related to testosterone but not the same. The effects you mention are for steroids, not natural testosterone.
Testosterone and Androstenone (primary ingredient of most steroids) are exact matches. The receptors engaged are the same. The structure of the proteins is the same. The post metabolites are the same.
trek. You do realize that castration is the removal of testes right? You'd still have "the little guy around" you wouldn't, however, have his two friends.
Or the urge to use the little guy.
trekgeek1
5 / 5 (2) Nov 03, 2010
trek. You do realize that castration is the removal of testes right? You'd still have "the little guy around" you wouldn't, however, have his two friends.


Yeah, but like Skeptic_Heritic said, I kind of want the whole "package". You can't do much without the whole gang present.
Slotin
1.1 / 5 (18) Nov 03, 2010
No wonder, the turtles are so long-living creatures. Women have slower basal metabolism, they prefer to live in quiet and they're more careful regarding healthy living style. In some studies the testosterone level was directly linked to telomerase activity.

http://linkinghub...)00392-8
Ideoplastic
not rated yet Nov 06, 2010
I'm curious to know what this theory presumes about women with higher levels of testosterone.

If the first proposal had any validity, we wouldn't have noticed a longevity gap until the last century and before when there was a greater gendered division of labor. Especially for the lower classes, like farmers, women didn't have the luxury of not working. 1950's revisionist history.
otto1932
3.3 / 5 (3) Nov 06, 2010
well at least now we know the secret to eternal life: castration at an early age, maybe in the womb!
You're not wrong. The ability to reproduce, and all the emotional and physical baggage that goes with it, produce the stress and compulsion that wastes most of our time and kills us early.

Sex and it's accoutrements will be discarded and outsourced some time in the future and the people will be much better off for it. Human cultures will as a result be unrecognizable. The meek will have inherited the earth.
otto1932
not rated yet Nov 06, 2010
I'm curious to know what this theory presumes about women with higher levels of testosterone.

If the first proposal had any validity, we wouldn't have noticed a longevity gap until the last century and before when there was a greater gendered division of labor. Especially for the lower classes, like farmers, women didn't have the luxury of not working. 1950's revisionist history.
Farming was a blip on the evolutionary scale. The disparity would have developed in the Pleistocene, when men hunted and fought and the women foraged while carrying fetuses with oversized heads which caused their pelvises to widen and their metabolisms to slow.
Ravenrant
4.7 / 5 (3) Nov 06, 2010
I can't see any logical reason why they .... sorry have to go, my wife is yelling at me about something.
rexalfielee
not rated yet Nov 10, 2010
Fairly nonsense. Until recent decades women had a poor history of surviving childbirth & men in general outlasted them. Their life expectancy wasn't that great & men would have to find another female to help raise any previous children while they went out hunting. Recent life expectancy changes have changed all of that. This whole article is crap!
S9A9R9
not rated yet Nov 10, 2010
Perhaps a test of the theory could be seahorses. They are fish not mammals, but perhaps some aspects apply. The male seahorse has the womb structure where the female places her eggs, the female goes off, to make more eggs and presumably to tend her much large territory. Some species form pair bonds, some do so at times... could be an interesting comparison to the human situation. Which seahorse gender generally lives longer?
winthrom
not rated yet Nov 10, 2010
At the end of WW1 and again at the end of WW2 there was a surplus of women in all the countries that took part in the fighting. perhaps the longevity of women in human society has characteristics different than mice.

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