The Paradox
What actually causes aging and why do people eventually die? 7/8/2011 12:49AM Reply | Return to Index | Report Post
On the surface this is a stupid question, but let me explain...
Most people die from an accident, disease, or cancer but even those that are lucky enough to be healthy in all aspects and fit at an old age still die...why?
Does our brain or heart have a predestined time clock?
Does our body get inefficient with dispersing amino acids, vitamins, minerals?
Also why is there a difference in life span between species, even when biologically we are so similar (dogs relatively short, sea turtles long, and humans in the middle)?
Good art
RE: What actually causes aging and why do people eventually die? 7/8/2011 1:50AM - in reply to The Paradox Reply | Return to Index | Report Post
its a biological scipt. the process of change that need not be a bad think, natural. but so scared we are of this. I met a guy at an aids hospice , excited by his next adventure, death. I amscaared shitless,,but none the less wee've been doing this this thing since time was born so I hope it will be easy and not freak.
Balzac
RE: What actually causes aging and why do people eventually die? 7/8/2011 2:19AM - in reply to The Paradox Reply | Return to Index | Report Post
Dying has something to do with telomeres shortening, cell replication having a finite number, DNA mutations etc. If enough of those little guys function poorly or die, organs will shut down.
slurp
RE: What actually causes aging and why do people eventually die? 7/8/2011 2:59AM - in reply to The Paradox Reply | Return to Index | Report Post
Stress & junk food
Alf Shrubb
RE: What actually causes aging and why do people eventually die? 7/8/2011 3:18AM - in reply to The Paradox Reply | Return to Index | Report Post
Every living entity on this planet has a limited life span.
The planet itself has a limited life span and will die when the suns also limited life span gives out.
Were told the whole Universe will eventually die - dont forget it only came into being from something the trillion, trillionth the size of the smallest matter we know today, a proton - and expanded such that in less than a minute, it was a million, billion miles across and still growing very fast.
I assume when the Universe finally gives up the ghost, in billions of years time, the whole process will start all over again.
And you enquire why puny humans should live forever?
Med School Runner
RE: What actually causes aging and why do people eventually die? 7/8/2011 3:29AM - in reply to The Paradox Reply | Return to Index | Report Post
As I see it, you seem to have two questions:
1. Why do people age?
2. How do people die of "natural causes?"

I'll do my best (with my limited knowledge) to address them:

1. The general consensus is that cells replicate less quickly with each successive mitotic division. This doesn't apply to germ cells (or to stem cells, for the most part). One theory is that cells have "telomeres" that are extensions at the end of their chromosomal DNA that get successively chopped off bit by bit with each cell division. Eventually you start chopping off important DNA, the cell accumulates deleterious mutations, and it dies. Aging researchers are investigating ways of lengthening these telomeres (ie. via telomerase).

2. As we age there are a number of degenerative processes, whether it is neurological (ie. MS, Parkinsons, Alzheimers), cardiovascular (MI, heart failure), neurovascular (stroke, hemorrhage), or cancerous. (Scary fact: When you get old, almost EVERYONE has cancer. It's just that most of the time it's not in a place that messes with your biological functions). All these conditions seem to occur in people who live healthy lifestyles, and Parkinsons and Alzheimers have staggeringly high rates of incidence in the elderly. Each one of these degenerative diseases has a different etiology.

Now, you might ask, why the hell does this have to occur? The answer to this is simple: evolution. There is no evolutionary incentive for humans (or any other organism for that matter) to live indefinitely. Our biological clock has been optimized to produce children and raise them until they are old enough to have children of their own. Society has pushed back this expectation of child rearing about a decade (or more). Since evolution works by "who produces the most viable offspring," pretty much anything you do after reproductive age has no effect. Therefore, there was no "reason" for us to develop innate protections against the aforementioned degenerative diseases.

Hope this helps.
Med School Runner
RE: What actually causes aging and why do people eventually die? 7/8/2011 3:37AM - in reply to The Paradox Reply | Return to Index | Report Post
It isn't clear from my post, but you can make the connection that the different lifespans between species has to do with reproductive strategy and time spent evolving.

Generally speaking, if the offspring require more time to be raised, then the lifespan of that species will necessarily be longer. Additionally, the longer period of time that an organism is able to produce offspring, the more of an "advantage" it will have to dominate the gene pool. I think that sea turtles can produce offspring late into life, and such there is an evolutionary incentive for them to live longer. (Unlike humans whose reproductive days are well established to be finite).

Organisms that take a "shotgun" approach to mating, such as insects and most fish, produce as many offspring as possible in the hopes that a few might survive their introduction to the world and reach mating age. They also reach that mating age rather quickly, and thus have pretty short lifespans.

I do not know the study offhand, but I think it was shown that entering puberty later was correlated with a longer life expectancy. Also, due to a number of confounding factors (many of them contributing to very early puberty), the current generation in America is the first... pretty much ever... to have a lower life expectancy than the previous one.
Kre
RE: What actually causes aging and why do people eventually die? 7/8/2011 6:57AM - in reply to The Paradox Reply | Return to Index | Report Post
It's a good thing we do age. I think the world would be a very strange place if once we were born that was the end of the aging process. Imagine the world with a bunch of 8 ounce babies crawling around.
)<ON#H
RE: What actually causes aging and why do people eventually die? 7/8/2011 7:18AM - in reply to Kre Reply | Return to Index | Report Post
Trolling on Letsrun
Hermione
RE: What actually causes aging and why do people eventually die? 7/8/2011 7:24AM - in reply to The Paradox Reply | Return to Index | Report Post
free radicals destroying the body.
Citizen Runner
RE: What actually causes aging and why do people eventually die? 7/8/2011 7:25AM - in reply to The Paradox Reply | Return to Index | Report Post
You might want to download this podcast onto your MP3 player for your next run. In this episode they explore some of the genetic basis for aging.
http://www.radiolab.org/2007/jun/14/
Teg
RE: What actually causes aging and why do people eventually die? 7/8/2011 8:45AM - in reply to Citizen Runner Reply | Return to Index | Report Post
It is kind of freaky how giant tortoises show extremely slow rates of aging.
They can live for hundreds of years.
A tortoise that James Cook picked up on his travels lived until the 1960's and one that Darwin brought back on the Beagle recently died.
Can you imagine what you would see change in the world from Cook's time until now?
That one was as old as the USA. Imagine living through the American Revolution, the Civil War and then a couple of WW's.
Irk
RE: What actually causes aging and why do people eventually die? 7/8/2011 9:03AM - in reply to Kre Reply | Return to Index | Report Post

Kre wrote:

It's a good thing we do age. I think the world would be a very strange place if once we were born that was the end of the aging process. Imagine the world with a bunch of 8 ounce babies crawling around.


Most human new borns weigh a tad over 8 ounces. They also don't crawl.
Class of 73
RE: What actually causes aging and why do people eventually die? 7/8/2011 9:12AM - in reply to The Paradox Reply | Return to Index | Report Post
Time.