why cant human live forever

[kok3000]

if u see human body as a machine,its income energy and use the energry,its seems it can work forever.

[qrasy]

Human can't grow forever, however the organs are able to produce hormones for growing?

 

I believe that its because after human body have developed fully, the organ became worse and worse, and will die.

Human consists of cell, perhaps there are a limited number of cell reproduction so that human can't live forever.. I wonder why cells should eventually die in relatively short time.

But I know even a machine cannot work forever... It would be broken.

[rakuenso]

wow.

[the tree]

If you see the human body as a machine...

Cars, washing machines, lighters et cetera will all eventually fall apart and become useless.

[T-Nemesis]

Theoretically humans could live forever, if injury is taken out of the equation. No one ever dies of 'old age', they die of medical complications which are a result of old age. If we can cure those complications than we can live for much longer.

 

I read just a month ago that there will be a huge leap in the life expectancy of humans in MEDCs. For now, it's predicted people of 65 will live until 90. And it's also thought that people with a low calorie diet (by low calorie I don't mean malnourish) will live slightly longer.

[rakuenso]

are you insane?

 

"injury"? injury in the perfect sense would mean that there would be no free-radicals, meaning no oxygen, meaning no way for the lungs to function, meaning no haemoglobin to the brain, etc. etc.

 

where did you read that there would be a huge leap in life expectancy? don't believe everything you read, we've trying to find a fountain of youth for the past 10,000 years.

[T-Nemesis]

are you insane?

"injury"? injury in the perfect sense would mean that there would be no free-radicals' date=' meaning no oxygen, meaning no way for the lungs to function, meaning no haemoglobin to the brain, etc. etc. [/quote']

 

Don't be so trivial, you know what I meant.

 

 

where did you read that there would be a huge leap in life expectancy? don't believe everything you read, we've trying to find a fountain of youth for the past 10,000 years.

 

The leap is already beginning. If the life expectancy is now already 90 for people that are 65, that's a pretty significant jump. Things will only get better.

[Bluenoise]

Theoretically humans could live forever' date=' if injury is taken out of the equation. No one ever dies of 'old age', they die of medical complications which are a result of old age. If we can cure those complications than we can live for much longer.

[/quote']

 

That's not true

 

Aging in itself is a "complication", Telomeres shorten, radicals irreversibally damage mitochondrial function and more.

Your body can only take so much damage of this kind before it can't function properly. When someone is 110 and spontaneously dies of a heart attack it's not a "medical complication".

[rakuenso]

Don't be so trivial' date=' you know what I meant.

 

 

 

 

The leap is already beginning. If the life expectancy is now already 90 for people that are 65, that's a pretty significant jump. Things will only get better.[/quote']

 

 

No I actually have no idea what you meant. You can't use such generic terms like injury when it comes to biology, you need to be precise and accurate (because thats how science works).

[Yggdrasil]

The leap is already beginning. If the life expectancy is now already 90 for people that are 65, that's a pretty significant jump. Things will only get better.

 

Here's an interesting fact. While the life expectancy of humans has increased significantly over the past 100 years, the maximum human life span has not increased at all. We still do not see people living past a maximum age around 120 (although more people are beginning to aproach this theoretical maximum). So, while we have been able to combat the causes of premature death with modern medicine, we have done little to combat the actual mechanism of aging.

[thorN]

It depends how you look at it (and how much Stephen Baxter, etc, you've read).

 

I understood it that the reason was died (simply put,) is because oxygen is basically a combustable fuel. It's necessary for life, but really is a highly reactive and corrosive substance (think rust, fire etc.).

 

We could live longer if we used oxygen at a slower rate- like whales and tortoises. However, would you want to give up your dexterity and speed of thought? I think it's a compromise.

 

Also, We live longer by becomming a different sort of life. Moving from organic materials to computers is a fun idea.

[dttom]

That means the death of human or other speices is because of the over-demage of organs inside their bodies caused by oxygen(not only oxygen but may be many other substances)? But why the organs of someone dead can be instal to another's body, and still functioning? I don't think the death of livings is just based on the demages of internal organs only, may be there're many other factors...

I'm not sure, just my opinion...

[scientistsahai]

I have been keenly following this. Well I can say that beacuse the life expectancy has increased and max life not because that was not on the immediate priority. We wanted to save those who should be and not who wants to increase his/her life span. Moreover, the low cal, high protein, and fit people live longer as they have reduced the activity of the cells and hence the damage.

This by some time increases their life, but we cannot live forever(as of now).Although some indian priests lived for much more than people live today and had their life span over 150 yrs. But since no recorded evidence is available, it cannot be proved now, but is well documented in the writings.

Also, there is lot more than we are aware of about aging and apoptosis. A lot of research has shown that it is a necessary evil and also helps in maintaining the homoestasis of the body for long. When this is broken that we fall sick or become prone to diseases. So the key for now is to maintain a healthy active and joyful living.

[thorN]

Indeed, dttom, it's not just oxygen, there's all the "radicals" earlier posts have discussed.

 

I thought that it wasn't the organs that "wore out", but instead the helices of DNA in every cell are sort of "burned out", so they can no longer divide properly. However, IANAB (i am not a biologist )

[sanjaygeorge]

tHEIR are certain proteins in our body which stop synthesising after certain age. That is why we start aging.

[dttom]

Indeed' date=' dttom, it's not just oxygen, there's all the "radicals" earlier posts have discussed.

 

I thought that it wasn't the organs that "wore out", but instead the helices of DNA in every cell are sort of "burned out", so they can no longer divide properly. However, IANAB (i am not a biologist )[/quote']

If the DNA is burned out gradually, the proteins that the organs composed of will be still demage continuously. Then do you mean that organs of old people is not suitable for transplantation?

[CanadaAotS]

The reason we get old and age, is because genes that are beneficial to us when were young aren't really needed as we get older, since supposedly the population has less of a chance of reaching advanced age.

 

Besides medicine, its evolution thats increasing age expectancy because people are having (and are able to have) children at an older age.

 

The average age of people having children has been increasing for a long time.

This 'naturally' increases life expectancy through evolution.

[thorN]

If the DNA is burned out gradually, the proteins that the organs composed of will be still demage continuously. Then do you mean that organs of old people is not suitable for transplantation?

 

I think there's an age limit on donations, yeah. It's 17-50 or something, the NHS sent me a creepy letter on my 17th birthday asking for my body parts.

 

The average age of people having children has been increasing for a long time.

This 'naturally' increases life expectancy through evolution.

I don't understand the cause/effect for life expentancy to rise here?

I thought that longer lifespan was due to improved medicine and hygiene?

[Mokele]

But why the organs of someone dead can be instal to another's body, and still functioning?

 

Because you have't had enough time for your organs to become ireeparably damaged by oxygen if you get hit by a truck at age 25.

[BhavinB]

I'm surprised noone has said this yet, making me wonder if my answer is correct at all.

 

However, I was taught that the reason our function decays over time has to do with DNA replication. There are these molecules called DNA polymerase which zip along DNA strands creating copies as they go at incredible rates. It is said that there are correction mechanisms as well but every now and then, a cell with improper DNA is created. Over the years, there are more and more of these improperly made DNA cells which leads to decay of body functions in all aspects of the body...leading to death obviously.

[Mokele]

That's part of it, yes. The trick is figuring out how much each of the various probable causes does.

[Bluenoise]

I'm surprised noone has said this yet' date=' making me wonder if my answer is correct at all.

 

However, I was taught that the reason our function decays over time has to do with DNA replication. There are these molecules called DNA polymerase which zip along DNA strands creating copies as they go at incredible rates. It is said that there are correction mechanisms as well but every now and then, a cell with improper DNA is created. Over the years, there are more and more of these improperly made DNA cells which leads to decay of body functions in all aspects of the body...leading to death obviously.[/quote']

 

Well the way that kills you is cancer. Any cell that is too damaged to keep on going dies, those that "evolve" to grow fast keep on going. Eventually a cell will "evolve" that can bypass whatever keeps your other cells in harmony. It becomes cancerous.

But mutations leading to organ failure? I doubt if anyone has ever had any other significant problems (besides cancer) from amassing point mutations in their genome.

Mitochondria are another story though.

[kok3000]

thanks for reply ,every one

[Donut.Hole]

Sorry, but humans can't live forever. At the start of your life, you produce more cells than those that are dying. Therefore, you grow. At mid-age, the production and death-rate is around the same, so you don't grow anymore. When you get old, stem cells, which are needed to produce other cells, start dying, so more cells are dying than being created. Eventually, something's gotta go.

 

But theoretically, if all organs are maintained carefully, you could live for a long time until you've got too few cells.

 

Also, immortality could be achieved by using stem cells to grow replacement organs.

[Rune175]

I know I'm a little late for this thread, but I did a little poking around before posting.

 

First of all the talk about the air is damaging our body. True that e.g. the free radicals have a negative effect on our body. Some posts suggested earlier that it was possible to prolong the life of some worms if the air didn't do any damage. The problem to this is, that if it was possible to "clean" the air, so it will have no negative effect on our body, should we all then live in small rooms or walk around wearing spacesuits, so we can live longer? Probably not, because we can't clean all the air on this planet. But even if we can't live 24 hours with air, which does not damage our body, then maybe we can some of the time. Humans sleep about 8 hours a day, 33% of our lives, so what if it was possible to create a non toxic environment when we were sleeping? Saying a small bedroom with super clean air. Even though we could't be in that environment the whole day, then we, as humans, would surely gain a possitive effect from that

This is of course all in theory, but I'm sure that with the current technology we have, it would be possible.

 

Which leads we to the next question, that was also discussed in this thread previously. If stem cells and other cells that we lose, due to a failing ability to regrow the cells, if the process can be reversed.

Again a very interesting question. Again, we have reached a new level regarding biochemical technology, and we are able to regrow cells, that seemed impossible 20 years ago. It is even possible to clone a human using the DNA from a fingernail!

 

Therefore I can't see anything that should prevent such a method - to activate the stem cells and DNA replicators so we won't age at the same level. A good example is growth hormones or dwarf hormones if you like. That hormone makes the body grow to a level that is likely to the same state, as if you were still a teenager (roughly said). Again, I don't see anything that would make it impossible to create such a hormone, that could keep the stem cells and DNA replication cells functioning over a long periode of time.

 

One of the disadvantages is, that it is never a good idea to tamper with the human nature. A human is at our current state "builded" to last about 75-80 years. To prolong life with maybe 50 years using hormones or other kind of medical wonders could be a bad idea.

 

One last thing. As discussed in this thread why humans live longer in average lifespand - but our maximum age does not increase the answer is very simple. Today, we are able to cure most diseases - and the fact that the incidens regarding sudden infant death (SID) have been decreased. Meaning that we don't live longer, we are just better to keep people alive!