Life expectancy - how long can humans live?

[revots33]

In 1900 U.S. life expectancy was 47 years. In 2000 it was about 77 years. In terms of how long human beings have existed, that is a huge jump in only 100 years.

I have a feeling if you told someone in 1700 that people would routinely live to 80 or 90, they would have laughed at you.

So at what point does scientific progress against disease no longer matter, and the human body simply gives out?

In other words, how long can humans possibly live? Is 200 years out of the question? How about 300?

[vhawk01]

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In 1900 U.S. life expectancy was 47 years. In 2000 it was about 77 years. In terms of how long human beings have existed, that is a huge jump in only 100 years.

I have a feeling if you told someone in 1700 that people would routinely live to 80 or 90, they would have laughed at you.

So at what point does scientific progress against disease no longer matter, and the human body simply gives out?

In other words, how long can humans possibly live? Is 200 years out of the question? How about 300?

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I think life expectancy is a horrible measure of what you are trying to get at. The life expectancy in 1900 may have been 47, but there were still probably a bunch of people living to be 70 or 80, and perhaps one or two 100 year olds. Now, more of us are reaching advanced age, but that has nothing to do with how long it is possible for us to live.

That being said, I have absolutely no idea what the answer to your question is. Sorry. Not sure if anyone can really give a legitimate answer, or even a reasonable range. There are probably different answers depending on your premises. How long can the human brain continue to function? What are the chances someone could live 150 years and avoid everything, i.e. accidents, cancer, disease, homicide? Are we allowed to replace all of the parts? None of them? All but the brain?

[Silent A]

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In 1900 U.S. life expectancy was 47 years. In 2000 it was about 77 years. In terms of how long human beings have existed, that is a huge jump in only 100 years.

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The biggest reason life expectancy was so low was that infant morality was so much higher. It was perfectly common for people to survive to their 70s if they could make it past the first 5 years.

For example, there are places in Africa where the under 5 mortality is close to 30% (about 2/3 of these deaths happen in the first year).

So say you have a country where 30% of the populations dies at an average of 1 year, and 70% dies at 80.

Average life expectancy = 0.3(1) + 0.7(80) = 56

Modern medicine can lower under 5 mortality to about 0.5%. If nothing else changes then ...

Average life expectancy = 0.005(1) + 0.995(80) = 79.6

A difference of close to 25 years.

[Silent A]

I should also add that there were about twice as many births per woman back then, so this makes the infant mortality effect even stronger.

[vhawk01]

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[ QUOTE ]
In 1900 U.S. life expectancy was 47 years. In 2000 it was about 77 years. In terms of how long human beings have existed, that is a huge jump in only 100 years.

[/ QUOTE ]

The biggest reason life expectancy was so low was that infant morality was so much higher. It was perfectly common for people to survive to their 70s if they could make it past the first 5 years.

For example, there are places in Africa where the under 5 mortality is close to 30% (about 2/3 of these deaths happen in the first year).

So say you have a country where 30% of the populations dies at an average of 1 year, and 70% dies at 80.

Average life expectancy = 0.3(1) + 0.7(80) = 56

Modern medicine can lower under 5 mortality to about 0.5%. If nothing else changes then ...

Average life expectancy = 0.005(1) + 0.995(80) = 79.6

A difference of close to 25 years.

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Do you know if there is some better measure of this, then? Perhaps something like "Life expectancy of the 90th %ile?" I guess simply basing it on "Oldest living human" serves the purpose, but it isn't as interesting.

[Piers]

So how long before we will have identified the genetic ‘defects’ that cause most forms of death and developed a way of changing peoples genetic code on the fly.

[arahant]

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In 1900 U.S. life expectancy was 47 years. In 2000 it was about 77 years. In terms of how long human beings have existed, that is a huge jump in only 100 years.

[/ QUOTE ]

The biggest reason life expectancy was so low was that infant morality was so much higher. It was perfectly common for people to survive to their 70s if they could make it past the first 5 years.

For example, there are places in Africa where the under 5 mortality is close to 30% (about 2/3 of these deaths happen in the first year).

So say you have a country where 30% of the populations dies at an average of 1 year, and 70% dies at 80.

Average life expectancy = 0.3(1) + 0.7(80) = 56

Modern medicine can lower under 5 mortality to about 0.5%. If nothing else changes then ...

Average life expectancy = 0.005(1) + 0.995(80) = 79.6

A difference of close to 25 years.

[/ QUOTE ]

Do you know if there is some better measure of this, then? Perhaps something like "Life expectancy of the 90th %ile?" I guess simply basing it on "Oldest living human" serves the purpose, but it isn't as interesting.

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Gerontologists tend to look at the whole curve (of survival). If you just want a single number, 90th percentile isn't so good because that changes when you eliminate death causes...need maybe 99th. No one really focuses on mortality rates at the super high ages because it's not possible to get enough data. A lot of studies of the super-old just use 'everyone over 100'.

In answer to the OP, it's hard to answer exactly, but the current maximum lifespan is around 120, and no one that I'm aware of believes that it has moved at all over the last 100 years. As other posters pointed out, what we've seen is a squaring of the survival curve, so that more people live to a very old age and then start to drop.

All sorts of interventions can increase the average lifespan, but the only thing that appears to increase the maximum lifespan (i.e., that could get you past 120) so far is calorie restriction. Possibly resveratrol, though that is pretty preliminary.

[FortunaMaximus]

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So how long before we will have identified the genetic ‘defects’ that cause most forms of death and developed a way of changing peoples genetic code on the fly.

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The two things are both different problems with their own massive 'unknowns', but I figure that's obvious.

As for the first one, medical science is making inroads, starting to map out code, etc. There still needs to be a paradigm shift in bioinformatics, which is still in its relative infancy. Specifically a simulator that is capable of assessing what changes will do over thousands of generations. And it has to be pretty damn accurate.

I guess we're at a stage where we are going to be able to literally rewrite ourselves from the soles up. But Hippocrates to Jarvik took quite awhile. Given the acceleration of tech development for us, and the realization of the cosmetic market becoming a major player in R and D, etc. after the first initial breakthroughs... (Human vanity ftw as a motivational tool)

You should be able to go to the barber for a trim, a shave, and a re-tint of your skin and hair color by the sixties.

[tolbiny]

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I have a feeling if you told someone in 1700 that people would routinely live to 80 or 90, they would have laughed at you

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the big life expectancy jumps were mostly due to reductions in infant and child mortality, not increases in the maximum.

[jman3232]

the real question is about happiness as we age and the ability to actually live life

[flatline]

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So at what point does scientific progress against disease no longer matter, and the human body simply gives out?

In other words, how long can humans possibly live? Is 200 years out of the question? How about 300?

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Scientific progress will eventually change the human body such that death is no longer inevitable at all. We only die because that is how life evolved. Science will be able to change this; there is nothing fundamentally stopping this. The only question is whether we will live to see it (well, ok, there's a lot more questions than that).

[vhawk01]

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the real question is about happiness as we age and the ability to actually live life

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Right, and this is the greatest triumph of medicine over the last 100 years. It isn't necessarily that the oldest people are living longer, but so many are surviving into middle-age, and the quality of life for these middle-aged people is vastly improved. Todays 60 year olds are yesterdays 45 year olds. This improvement may be flattening out or even changing for the worse, because I seem to recall that the last two years, children born are expected to live shorter than their parents for the first time in a long time.

[Woolygimp]

Human beings cannot live longer than 125 years. It's genetically impossible for that to happen according to research in the field, and they have an equation, and it's like X/1000 people live to 80, 90, 100, 110, 120.

It's like 1 in hundreds of millions to live past 115, and like 1:1 billion to live past 118.

There's a lot of science behind it, and they can give you some pretty in depth numbers, but at some point humans just 'give out' and their cells are no longer capable of self-repair.

For what it's worth life expectancy has nothing to do with it. You need to search for research involving maximum lifespan.

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R/PS: Who is the oldest recorded living person?

RM: Jeanne-Louise Calment of France, who died in 1997, lived to be 122 years and five months. This woman was quite a character, if you read about her. She was bright and spry into her later years. She took up fencing at age 87. I hesitate to say this, but she smoked until she was 117. The only reason she quit is because she got tired of asking people to light her cigarettes for her. She couldn't see well enough to do it herself.









R/PS: Why is 125 the magic number?










RM: It's evolved. The program, so to speak, within our system has evolved to the point that we just can't get beyond that. It's a matter of repair. We only have so many repair systems that have evolved over millions of years. The best an individual can do is keep repairing damage, up to a certain point, and then you just can't do it anymore. Long-lived animals have much better repair systems then short-lived animals. That's genetic and it's evolved that way.

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[vhawk01]

[ QUOTE ]
Human beings cannot live longer than 125 years. It's genetically impossible for that to happen according to research in the field, and they have an equation, and it's like X/1000 people live to 80, 90, 100, 110, 120.

It's like 1 in hundreds of millions to live past 115, and like 1:1 billion to live past 118.

There's a lot of science behind it, and they can give you some pretty in depth numbers, but at some point humans just 'give out' and their cells are no longer capable of self-repair.

For what it's worth life expectancy has nothing to do with it. You need to search for research involving maximum lifespan.

[ QUOTE ]
R/PS: Who is the oldest recorded living person?

RM: Jeanne-Louise Calment of France, who died in 1997, lived to be 122 years and five months. This woman was quite a character, if you read about her. She was bright and spry into her later years. She took up fencing at age 87. I hesitate to say this, but she smoked until she was 117. The only reason she quit is because she got tired of asking people to light her cigarettes for her. She couldn't see well enough to do it herself.









R/PS: Why is 125 the magic number?










RM: It's evolved. The program, so to speak, within our system has evolved to the point that we just can't get beyond that. It's a matter of repair. We only have so many repair systems that have evolved over millions of years. The best an individual can do is keep repairing damage, up to a certain point, and then you just can't do it anymore. Long-lived animals have much better repair systems then short-lived animals. That's genetic and it's evolved that way.

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You have a cite for this? I know there is research going on in this, but I didn't know it was entirely settled. I was also under the impression that caloric restriction has a large impact. Tell me where you read this?

[revots33]

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For what it's worth life expectancy has nothing to do with it. You need to search for research involving maximum lifespan.

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Yes you are all right, maximum lifespan is what I was getting at, not life expectancy. My apologies.


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but at some point humans just 'give out' and their cells are no longer capable of self-repair.

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ok fair enough but what about science finding a way to repair damage at the cellular level? Is this possible or a pipe dream?

i read an article about extreme calorie restriction diets and a lot of people who follow this are trying to keep themselves alive until the point of actuarial escape velocity (http://en.wikipedia.org/wiki/Actuarial_escape_velocity) is reached.

[Jetboy2]

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ok fair enough but what about science finding a way to repair damage at the cellular level? Is this possible or a pipe dream?

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Ray Kurzweil wrote a book called, "Fantastic Voyage" where he discusses radical life extension. He thinks that a combination of genomics, biotechnology and nanotechnology will soon allow humans to live extremely long lives.

[arahant]

[ QUOTE ]
Human beings cannot live longer than 125 years. It's genetically impossible for that to happen according to research in the field, and they have an equation, and it's like X/1000 people live to 80, 90, 100, 110, 120.

It's like 1 in hundreds of millions to live past 115, and like 1:1 billion to live past 118.

There's a lot of science behind it, and they can give you some pretty in depth numbers, but at some point humans just 'give out' and their cells are no longer capable of self-repair.

For what it's worth life expectancy has nothing to do with it. You need to search for research involving maximum lifespan.

[ QUOTE ]
R/PS: Who is the oldest recorded living person?

RM: Jeanne-Louise Calment of France, who died in 1997, lived to be 122 years and five months. This woman was quite a character, if you read about her. She was bright and spry into her later years. She took up fencing at age 87. I hesitate to say this, but she smoked until she was 117. The only reason she quit is because she got tired of asking people to light her cigarettes for her. She couldn't see well enough to do it herself.









R/PS: Why is 125 the magic number?










RM: It's evolved. The program, so to speak, within our system has evolved to the point that we just can't get beyond that. It's a matter of repair. We only have so many repair systems that have evolved over millions of years. The best an individual can do is keep repairing damage, up to a certain point, and then you just can't do it anymore. Long-lived animals have much better repair systems then short-lived animals. That's genetic and it's evolved that way.

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This isn't right.
Firstly, damage couldn't provide a theoretical upper bound on lifespan. If you can find someone who's 125 I can find someone who had a little less environmental insult and who will live a little longer.

The only known 'theoretical' limit on lifespan would be the loss of telomeres as cells divide. At some point, cells that need to divide run out of telomeres. But even that can be 'fixed' if we can genetically engineer longer telomeres, or some way to add on to them.

[kevin017]

The maximum lifespan has everything to do with the rate of aging, which we have very little ability to change, outside of calorie restriction as was mentioned earlier. People might make theoretical guesses as to a maximum age but they're all just guesses, and as time and technology progresses we will certainly live longer and longer.

[arahant]

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The maximum lifespan has everything to do with the rate of aging...

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Yes, but that's just tautological.

[Friedrich888]

The way I look at it is people who are 107 years old today were born in 1900. In 1900 conditions were drastically different than today. Would that same person, born in 2007, live longer ? I think there is some room for optimism but it isn't provable either way.

[Rduke55]

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extreme calorie restriction diets

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Have you seen those diets? Everytime I see something on this I wonder what's the point of living longer if you're living like that.