Longevity

Longevity is defined as long life or the length of a person's life (life expectancy). Reflections on longevity have usually gone beyond acknowledging the basic shortness of human life and have included thinking about methods to extend life. Longevity has been a topic not only for the scientific community but also for writers of travel, science fiction and utopian novels. The longest human lifespan on record that has been authenticated is the 122 years 164 days of Jeanne Calment, though fiction, legend, and mythology have proposed or claimed vastly longer lifespans in the past or future and longevity myths frequently allege them to exist in the present.


Presently

Various factors contribute to an individual's longevity. Significant factors in life expectancy include genetics, access to health care, hygiene, diet, exercise and lifestyle. Below is a list of life expectancies in different types of countries[1]:

* First World: . . . 77-83 years (eg. Canada: 80.1 years, 2005 est)
* Second World:. 65-77 years (eg. Russia: 67.1 years, 2005 est)
* Third World:. . . 35-60 years (eg. Mozambique: 40.3 years, 2005 est)

Tobacco smoking is generally accepted to significantly reduce longevity, and is one of the main statistical factors explaining differences in life expectancy between advanced nations. This may be offset by other factors; Japan, a country with a high rate of tobacco consumption, has one of the highest life expectancies in the world (81.15 years, 2005 est). Hong Kong, a dense 7 million people city with constant stress, recently reported a higher life expectancy than Japan (81.39 years, 2005 est)

Population longevities can be seen as increasing due to increases in life expectancies around the world:

* Australia: . . 80 years in 2002, 80.39 years in 2005
* Italy:. . . . . . 79.25 years in 2002, 79.68 years in 2005
* France: . . . .79.05 years in 2002, 79.60 years in 2005
* Germany: . . 77.78 years in 2002, 78.65 years in 2005
* UK: . . . . . . 77.99 years in 2002, 78.4 years in 2005
* USA: . . . . . 77.4 years in 2002, 77.7 years in 2005



Records

The current validated longevity records can be found in the list of supercentenarians. Notable individuals include:

* Jeanne Calment (1875-1997, 122 years and 164 days) - oldest person ever whose age has been verified by modern documentation; born 1875, lived to the age of 122. This defines the human lifespan, which is set by the oldest documented individual who ever lived.
* Shigechiyo Izumi (1865-1986, 120 years 237 days, disputed) - oldest male ever recognized by the Guinness Book of World Records; authentication largely questioned by modern conflation.
* Christian Mortensen (1882-1998, 115 years) - oldest male widely accepted by scholars



History

Reaching an old age has fascinated people for ages. There are many organizations dedicated to exploring the causes behind aging, ways to prevent aging, and ways to reverse aging. Despite the fact that it is no more than human nature to not wish to surrender to old age and death, a few organizations are against antiaging, because they believe it sacrifices the best interests of the new generation, that it is unnatural, or unethical. Others are dedicated towards it, seeing it as a form of transhumanism and the pursuit of immortality. Even among those who do not wish for eternal life, longevity may be desired to experience more of life, to provide a greater contribution to humanity.


Religion

The Bible contains many accounts of long-lived humans, the oldest being Methuselah living to be 969 years old (Genesis 5:27). Today some maintain that the unusually high longevity of Biblical patriarchs are the result of an error in translation: lunar cycles were mistaken for the solar ones, and that the actual ages being described would have been 13.5 times less. This makes Methuselah's described 72, still an impressive number bearing in mind the average life expectancy at the time. This rationalization, however, seems doubtful too since patriarchs such as Mahalalel (ibid 5:15) and Enoch (ibid 5:21) were said to have become fathers after 65 "years". If the lunar cycle claim were accepted this would translate to an age of about 4 years and 10 months. One Christian apologist claim is that the life span of humans has changed; that originally man was to have everlasting life, but due to man's sin, God progressively shortened man's life in the "four falls of mankind" -- first to less than 1000 years, then to under 500, 200, and eventually 120 years.

Non-fundamentalist Christians, skeptics and atheists tend to consider such stories to be among the longevity myths, noting that age exaggeration tends to be greater in "mythical" periods in many cultures; the early emperors of Japan or China often ruled for more than a century, according to tradition. With the advent of modern accountable record-keeping, age claims fell to realistic levels; even later in the Bible King David died at 70 years; other kings in their 30s, 40s, and 50s. The Bible also says that after those long living people died, God decided that humans would not be permitted to live more than 120 years (Genesis 6:3.)


Future

The mainstream view on the future of longevity, such as the US Census Bureau, is that life expectancy in the USA will be in the mid-80s by the year 2050 (up from 77 today) and will top out eventually in the low 90s, barring major scientific advances that can change the rate of human aging itself, as opposed to merely treating the effects of aging as is done today. The Census Bureau also predicted that the USA would have 5.3 million people aged over 100 in 2100.

Recent increases in the rates of obesity-related diseases, such as diabetes, hypertension, and heart disease, may however drastically slow or reverse this trend toward increasing life expectancy in the developed world.


Non-human biological longevity

Living:

* Methuselah (tree) - 4700-year-old bristlecone pine in the White Mountains of California, the oldest known living organism.
* Harriet - a 175-year-old Galápagos tortoise, the oldest known living animal.
* Cheeta - a 74-year old chimpanzee, the longest lived known chimpanzee.

Dead:

* Adwaitya - an Aldabra Giant Tortoise, died at 255 years old, the oldest known animal.
* A Bowhead Whale killed in a hunt was found to be approximately 211 years old, the longest lived mammal known.