
Your body wasn’t built to last: a lesson from human mortality rates - mrfusion
https://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/
======
Rainymood
As someone who is studying actuarial sciences ... if you use some real data
against the Gompertz you see that it doesn't really fit that well for very
small and very large ages. Which is why this guy Makeham did this

[http://en.wikipedia.org/wiki/Gompertz%E2%80%93Makeham_law_of...](http://en.wikipedia.org/wiki/Gompertz%E2%80%93Makeham_law_of_mortality)

As a student with a mathematics background (and boy do we love
'simplifications'). I can never stop theorizing and thinking about what would
happen if we would just insist on a maximum age of lets say 80. It will
probably never happen, but just think about it. It's both morbid and
fascinating in it's own sense.

~~~
wehadfun
So what happens at 80?

~~~
chiph
Your palm crystal blinks red and you go to Carousel.

~~~
brlewis
I had to google this reference.
[http://en.wikipedia.org/wiki/Logan%27s_Run#Film](http://en.wikipedia.org/wiki/Logan%27s_Run#Film)

------
fizixer
> ... no one understands why it’s true.

That's an unwarranted claim. Various quantities of interest of complex systems
more often than not follow certain statistical distributions. This is
especially true about natural systems.

Flip 100 coins, call it one trial. Perform such trials a large number of
times, a few hundred let's say. For each trial count the number of heads. In
the end create a histogram (frequency of N-head trials, N ranging from 0 to
100). It'll look like a gaussian distribution! The emergence of such
distribution feels strange, even though we pretty much know everything about
the system. (Incidentally this is related to the Central Limit Theorem).
Similar idea applies to human mortality distributions.

The best you could say is that these are very counter-intuitive
observations/facts.

~~~
emn13
In that case we understand what causes the Gaussian to emerge - lots of
individual coin flips. However, in human mortality, the underlying "coin flip"
\- i.e. the death-causing event - isn't so easily found. Particularly when you
consider that apparently the underlying cause seems to happen more frequently
as you age, which is kind of interesting when you consider that the physical
laws haven't changed - there's obviously some kind of emergent process going
on - but what and why? That's the question.

It wouldn't suprise me to learn that it's basically planned obsolescence -
i.e. that there's an evolutionary advantage to a species that cycles through
individuals as rapidly as possibly (while leaving enough time to produce a lot
of progeny).

~~~
a8da6b0c91d
> but what and why?

Iron and heavy metals accumulate in tissues over time. The tissue membranes
accumulate an increasing share of polyunsaturated lipids, which in turn
interfere with efficient metabolism. Many ways that biological tissue wears
out over time are well understood. It's not just some mystery.

~~~
emn13
That doesn't really ring true - after all, they're going to be passed to
newborns too. "Gunk" collects in tissues that are never replaced, but why does
that occur in the first place? Clearly, growing new tissue isn't a
biologically hard problem - when there's evolutionary pressure to do so,
several species evolved means to replace surprisingly large parts of their
body. Some insect metamorphose; crustaceans rebuild complete skeletons -
energetically, it's almost certainly hell of a lot cheaper to occasionally
replace bad bits than it is to procreate and lose the previous generation.
There's something else going on there.

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abandonliberty
The programmed senescence model fits with this observation quite well. It
argues that aging isn't the result of a breakdown or accumulated damage, but
rather a deterministic process based on our genetic programming.

Evolution programmed us to make a human, but it didn't program us to stop
developing. We're like a cake left in the oven. No one told the concrete
suppliers to go home, so they just keep dumping it everywhere on our completed
skyscraper.

We were built to die.

[http://www.senescence.info/programmed_aging.html](http://www.senescence.info/programmed_aging.html)

~~~
eevilspock
I get and agree with your first paragraph, but can't make sense of your
second.

~~~
CapitalistCartr
He is badly mixing metaphors. One baking, the other construction.

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ozborn
As someone with a biology background I find the conclusions a little too
general. Mortality curves are not only species specific, but particular for
that environment. A curve using saltwater crocodiles or lobsters would look
quite different with very high mortality for the young and limited mortality
for the very old. The curve for humans can (and has) been adjusted by human
action to give it a better shape - especially at extreme ages. So I think it
should be emphasized that the curve is not some mathematical unalterable fact
of life.

~~~
wyager
Lobsters are biologically immortal, I.e. their expected remaining lifetime
does not decrease with age.

[http://en.wikipedia.org/wiki/Biological_immortality#Lobsters](http://en.wikipedia.org/wiki/Biological_immortality#Lobsters)

~~~
comex
The text at your link contradicts your statement.

~~~
robot22
No it does not. Lobsters do not die from the effects of ageing. They die due
to a lack of energy to keep moulting. Straight from the text.

~~~
arsenide
"their expected remaining lifetime does not decrease with age." (emph
REMAINING) implies that two lobsters, at 1 and 10 years, each have the same
probability to live for some number X years in the future for some fixed X.
This seems to me a certainly false statement, where you claim otherwise. Can
you elaborate?

~~~
robot22
I think we agree, I replied to the wrong comment

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jostmey
Theoretical work by Fisher, Medawar, and Hamilton during the last century
pretty much explained why we see super-exponential decay in mortality
distributions. Their theories center around using the "Euler-Lotka Equation",
which estimates the number of descendants from an individual considering that
each member ages. You can then show that the effect of aging on fitness is
marginal, and hence not selected against.

This might be one of the more accessible papers:
[http://www.genetics.org/content/156/3/927.short#ref-10](http://www.genetics.org/content/156/3/927.short#ref-10)

~~~
jostmey
P.S. And yes, Mother Nature did not build us to last. Natural selection seems
to have little regard for longevity.

~~~
tachyonbeam
There are plants that seem to last indefinitely and never really die, this
one, for example:
[http://en.wikipedia.org/wiki/Chlorophytum](http://en.wikipedia.org/wiki/Chlorophytum)

I think the real issue is that when it comes to complex animals, it's much
easier to build a brand new one than to repair existing ones. Our genes encode
how to grow a human from scratch, but now how to deal with the myriad of
problems that can occur as a result of normal wear and tear. Repairing an
ageing body is a completely different problem from growing one.

We do have some DNA that deals with maintenance processes, but I think the
issue is that these processes inevitably can't cope. It's like trying to patch
up an old house. You can keep doing little fixes here and there, but at some
point, serious renovations are needed, and we're just not genetically equipped
to do that.

You have to wonder what it is nature could do anyway, if humans living to be
extremely old had been selected for. Old human bodies are so broken, we'd need
to be able to grow entirely new ones and shed body parts, even regrow brain
tissue. We'd need a metamorphosis on the level of what butterflies go through.

~~~
emn13
[citation needed] - wikipedia makes no mention of this extremely unusual
property.

Apparently some people think even bacteria age -
[http://www.sciencedaily.com/releases/2011/10/111027150207.ht...](http://www.sciencedaily.com/releases/2011/10/111027150207.htm)
(whatever that means in an organism that divides).

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methodover
Man, reading this gave me such a strange sensation. I began to read it over
lunch, and I was just hit with this wall of sadness. I looked around at the
people at the shop I was in, thought about everyone I know, and thought,
"We're all going to die."

It's weird, we all pretend like it won't happen. We do our best to live
without thinking about the fact that we have a X% chance of not making it to
our next birthday.

I thought about my friend from college who died of cancer a year or so ago. I
thought about my parents, who are quickly approaching those scary 1-in-1XX
odds of dying every year.

It's like there's this scary axe-murderer out there, who's killing people left
and right, and we all just do our best to ignore him. Because there's no
stopping him. He'll come for you... He'll come for all of us. The only thing
you can do is try not to think about it.

~~~
sebular
I believe that the best thing to do is to think deeply about it and explore
those feelings. Because it's inevitable, we need to accept and embrace it.

Picture any time before you were born. If it's not scary or sad to think about
that, then thinking about a time after you die shouldn't be any different.

If you're worried about the actual moment of transition, it's probably going
to be either too abrupt for you to really react to it (accident or violence),
or you'll be super tired/unconscious and it'll basically be a relief, like
sleep. This isn't a guarantee, but it's pretty likely.

As far as I'm concerned, as long as I can avoid a slow, painful death, it's
all good. This is why torturous murders/executions and outlawing euthanasia
are the most horrible things that people can inflict on each other-- you're
ruining a person's only shot at a good death.

~~~
sireat
The odds are pretty good today that you will go out slowly with a whimper, due
to a stroke, heart attack, cancer.

In fact looking at causes of death: [http://www.cdc.gov/nchs/fastats/leading-
causes-of-death.htm](http://www.cdc.gov/nchs/fastats/leading-causes-of-
death.htm)

Heart disease: 611,105 Cancer: 584,881 Chronic lower respiratory diseases:
149,205 Accidents (unintentional injuries): 130,557 Stroke (cerebrovascular
diseases): 128,978 Alzheimer's disease: 84,767 Diabetes: 75,578 Influenza and
Pneumonia: 56,979 Nephritis, nephrotic syndrome, and nephrosis: 47,112
Intentional self-harm (suicide): 41,149

Most of the causes can last a long time.

Even a heart attack might not kill you immediately these days you might linger
on for a bit due to timely medical care.

So you better be ready for some suffering just like Ivan Ilyitch.

------
smrtinsert
Immortality is such an awful goal. What is life if there is no beginning
middle and end? I can't begin to think of the resource constraints a
population would have if none of them have to die. I can only think life
evolved to die from immortality and should not go in reverse.

~~~
vectorjohn
That's your opinion. I think it's a mind bogglingly bizarre one, but sure. But
what isn't an opinion is the "resource constraints" idea. That's just wrong
and unrelated. There would need be no resource constraints. In fact, without a
workforce that gets old and dies, certain resources would be even more
plentiful. Certainly labor. Economies would have to adapt somewhat.

It is many people's (and my) opinion that death is one of the most tragic
facts of life we currently face. All that knowledge and personality and life
that makes up a person just disappears? What an idiotic process. If we can put
an end to it we should.

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Animats
Aging is a disease, not a wear-out problem. Now that most of the early-killer
problems have been solved, the remaining lifespan curve makes that clear.
There are specific evolved mechanisms built in to get the old people out of
the way so the species can progress.

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dsugarman
> Shown above are the results from a simulated world where “lightning bolts”
> of misfortune hit people on average every 16 years, and death occurs at the
> fifth hit.

I think that graph would look almost perfect if the decay was exponential
rather than linear. A better hypothesis would be every time you are hit by a
lightning bolt, you are twice as likely to be restruck every year. So if you
are hit and it was a 1/40 chance, next year would be a 1/20 chance until you
are hit 5 times.

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lazyjones
Obviously it isn't really working well yet, so newer versions with better DNA
are released and old ones get retired regularly. ;-) Perhaps we could have
fewer such DNA "updates" if we didn't mess with our environment (= living
conditions) so much that frequent adaptations are needed.

I'd really like to see a study that examines people's life expectancy when
they move (very early) from a modern environment to one that resembles their
parents' living conditions 10-20 years ago, the hypothesis being that their
genes would have adapted to cope with those conditions and not with more
recent changes, so they might live longer and healthier on average. Usually we
do the opposite, many people move from rural to urban areas, so they need to
adapt to more changes than those happening at an already fast pace in one
area.

(apologies for half-serious unscientific techie ramblings)

------
carapace
You know how the amoeba reproduces, right? It splits into two. So every
amoeba* alive today has been alive for hundreds of millions, perhaps billions,
of years.

*And all the other organisms that "reproduce" this way.

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1971genocide
As someone who have never had to deal with the question of mortality. this is
really disturbing !

The frustrating part is if people throw enough money at the problem it can be
solved ! its not like the problem of time-travel or anti-gravity. Ageing in
just a computation problem that can be solved with enough data !

I wished my fellow humans spent a large part of the economy trying to solve
it.

------
clord
Um, Last I checked, not many human machines can continuously operate up to 100
years. Most robots and machines like cars are considered "long life" if they
last 30. Seems to me the human body is built to last.

~~~
Retra
Machines are not self-repairing.

~~~
vonmoltke
Nor can those machines acquire their own energy.

~~~
clord
That was exactly my point. thank you. Humans last longer than machines
_because_ we self-repair and acquire our own energy. Last I checked, human-
made machines do neither of these things. Not sure why I was down voted for
pointing that out?

~~~
Retra
You were saying that the human body is built to last because it barely lasts
longer than machines. But comparing the human body to a machine is fruitless;
the ability to self repair and collect our own energy should allow us to last
almost indefinitely, not a mere 80 years. 80 years is more like you would
expect from a machine.

Those capabilities -- self repair and energy collection -- should allow many
orders of magnitude greater longevity. The fact that they haven't indicates
that those capabilities are not optimized for longevity. Ie., we were not
'built to last.'

We were optimized for species-longevity through reproduction, not individual
longevity. The fact that we've existed as a species for hundreds of thousands
of years is more like what you should expect from something that is built to
last.

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alecco
Isn't this pseudoscience?

~~~
drzaiusapelord
Not really, but seems to be basic statistics to me with some obvious trickery
in place. My complaint is that he kinda glosses over (cut outs?) high infant
mortality which would bend the curve in a not so aesthetically pleasing way. I
imagine elderly mortality would do the same towards the end of the curve.
People in their 80s and 90s aren't doubling mortality rates in 8 years,
they're doing so practically yearly.

wikipedia: The Gompertz–Makeham law of mortality describes the age dynamics of
human mortality rather accurately in the age window from about 30 to 80 years
of age.

So, he cuts off the high risk childhood, teen, and 20s and everyone over 80?
Yeah, that's how you get such a smooth graph. So not exactly pseudoscience,
but definitely dishonest. Seems to me there are a lot of people who think nice
clean graphs are 'beautiful' and try to fit in data and act pretentious about
some 'mystery' link to math or the universe or somesuch. The same way every
hack pop-science writer fits everything to the Fibonacci sequence. Uh, no, all
this seems to say is that if youre healthy enough to hit age 30, you probably
have a nice normalized mortality rate from then on to about 80.

Skipping the first 30 years and anything over 80 is the only way this
"beautiful" math and "mystery" works. When we include all ages, its a pretty
predictable graph:

[http://en.wikipedia.org/wiki/Gompertz%E2%80%93Makeham_law_of...](http://en.wikipedia.org/wiki/Gompertz%E2%80%93Makeham_law_of_mortality#/media/File:USGompertzCurve.svg)

Lots of craziness at first then a regular slope until the end.

