Aging theories

WellCookedFetus said:
Kumar,

Its also possible the pH imbalance is the result of aging not just the cause.
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WellCookedFetus,

Even if it is so, we can easily treat it & get the age increased. If we can know the reson/cause then furthur task can be easy. Is it not ok? :)
 
Raise stomach pH and you might increase your risk of ulcers and lethal stomach bleeding. At that age you stomach walls are paper-thin.
 
Is it after effect of aging? If we take care previously then?

However if ' tollerance effected' is something common on aging?

AGING CHANGES IN VITAL SIGNS

Normal body temperature does not change significantly with aging. Temperature regulation, however, is more difficult.

Because of changes in the heart, the resting heart rate may become slightly slower. It takes longer for the pulse to speed up when exercising, and longer to slow back down after exercise. The maximum heart rate reached with exercise is lowered.

Blood vessels become less elastic. The average blood pressure increases from 120/70 mm Hg to about 150/90 mm Hg and may remain slightly high even if treated. The blood vessels also respond more slowly to a change in body position.

Although lung function decreases slightly, changes are usually only in the reserve function. The rate of breathing usually does not change.http://www.nlm.nih.gov/medlineplus/ency/article/004019.htm
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WellCookedFetus said:
longer life spans are rarely selected for because predators and disease get you first even if you would have lived longer, usually having children quickly is more selective pressure then living longer to have more children.
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Right. There is a tradeoff somewhere along the line and it seems to be about 80 years for homo sapiens. After the age of 80, the cost of keeping the body maintained outweighs any potential genetic benefits from more offspring even if we could reproduce into old age. Do u agree with this Fetus?
 
I would say the trade of is lower then that, our bodies degenerate after I primes in are early 20's. Evolution did not see a need for us to live in optimum condition past this, extended survival is do to modern science keeping people alive longer, it would take evolution a long time tie increase human life span based of are present trend of living longer and having children at older ages, even so I think that part of the reason why we live longer the many other mammals, we are a social species and older members are still helpful.
 
OK but do u think the theory is essentially right? It is a trade off between the cost of maintenance and benefit of offspring?
 
Yes of course, we live longer then most mammals because we can benefit are young longer, but we still grow old and die.
 
John Connellan said:
Paul: why wouldn't individuals which have a very long reproductive life be selected for? Lets say u have mutant people in the population who can give birth at 60/70 years of age. They should be selected for right?
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actually i think it can. hope i didn't give the impression that it can't

fruit fly artificial selection experiments have extended fruit fly life spans significantly

problem with mammals is the determinant number of eggs a female has, they obviously will run out at some time.
 
WellCookedFetus said:
longer life spans are rarely selected for because predators and disease get you first even if you would have lived longer, usually having children quickly is more selective pressure then living longer to have more children.
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this is not true.

delayed reproductive age is sometimes selectively advantageous. it depends on an organism's ecology, life history characterisitcs, etc.

reproductive age has great variability, there is NO evidence that there is directional selective force decreasing age at first reproduction.

there are some organisms that are born pregnant, and i think some cetacean species where age of first reproduction is in the 30's or 40's
 
paulsamuel,

Note the use of "usually" and "rarely", my statements are not all encompassing, there are vast exceptions.
 
WellCookedFetus said:
paulsamuel,

Note the use of "usually" and "rarely", my statements are not all encompassing, there are vast exceptions.
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oh yes, like the Order Mammalia

please keep me on ignore
 
John Connellan said:
OK but do u think the theory is essentially right? It is a trade off between the cost of maintenance and benefit of offspring?
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actually the theory's implication is the differential reproductive selective value of being young vs. being old
 
While whole grain foods are a good, natural source of silicon, the silicon from these foods is insoluble and cannot be directly absorbed in the gastro-intestinal tract. Silicon in food is solubilized by stomach acid into orthosilicic acid, which absorbs directly through the stomach wall and the intestine into the blood. Lower stomach acidity, whether due to illness or age, diminishes our ability to metabolize silicon from food sources. Aging is reported to be associated with an increasing gastric pH. In this view elderly people will have a decreased capacity to convert dietary silicates into bioavailable orthosilicic acid.
http://www.lef.org/magazine/mag2003/apr2003_report_silicon_01.html
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Aging is reported to be associated with an increasing gastric pH.
 
PJ, Our created early Aging in itself is like a disease. More mental stresses on aging are common. Mental stresses can effect stomach acidity.

..Medical literature and the bible have documented man attaining the age of 150 or older. With the advent of modern civilization and the self-abusive lifestyle homosapiens have developed, man's life span, in spite of today's great advances in medical technology, has been greatly shortened. While it is naturally possible to stay young longer and maximize our longevity,..
http://www.cdc-cdh.edu/hospital/cardio/chua1.html
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