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I can’t be the only one noticing all the pesky signs of ageing. I used to be 5ft 8in – now, at 63, it’s more like 5ft 7in. My vision, hearing, memory and hair aren’t quite what they used to be, just a few things that tend to wane as the number of candles on our birthday cake increases. Are there biological and scientific reasons behind all of these annoying signs? What is normal and what isn’t? And more importantly, can I slow them down? I consulted the experts to find out……..Continue reading…
Source: Telegraph
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Critics:
Most biological organisms have a naturally limited longevity due to aging, unlike a rare few that are considered biologically immortal. Given that different species of animals and plants have different potentials for longevity, the disrepair accumulation theory of aging tries to explain how the potential for longevity of an organism is sometimes positively correlated to its structural complexity.
It suggests that while biological complexity increases individual lifespan, it is counteracted in nature since the survivability of the overall species may be hindered when it results in a prolonged development process, which is an evolutionarily vulnerable state. According to the antagonistic pleiotropy hypothesis, one of the reasons biological immortality is so rare is that certain categories of gene expression that are beneficial in youth become deleterious at an older age.
Longevity myths are traditions about long-lived people (generally supercentenarians), either as individuals or groups of people, and practices that have been believed to confer longevity, but for which scientific evidence does not support the ages claimed or the reasons for the claims.
A comparison and contrast of “longevity in antiquity” (such as the Sumerian King List, the genealogies of Genesis, and the Persian Shahnameh) with “longevity in historical times” (common-era cases through twentieth-century news reports) is elaborated in detail in Lucian Boia’s 2004 book Forever Young: A Cultural History of Longevity from Antiquity to the Present and other sources.
After the death of Juan Ponce de León, Gonzalo Fernández de Oviedo y Valdés wrote in Historia General y Natural de las Indias (1535) that Ponce de León was looking for the waters of Bimini to cure his aging. Traditions that have been believed to confer greater human longevity also include alchemy, such as that attributed to Nicolas Flamel. In the modern era, the Okinawa diet has some reputation of linkage to exceptionally high ages.
Longevity claims may be subcategorized into four groups: “In late life, very old people often tend to advance their ages at the rate of about 17 years per decade …. Several celebrated super-centenarians (over 110 years) are believed to have been double lives (father and son, relations with the same names or successive bearers of a title) …. A number of instances have been commercially sponsored, while a fourth category of recent claims are those made for political ends ….”
The estimate of 17 years per decade was corroborated by the 1901 and 1911 British censuses. Time magazine considered that, by the Soviet Union, longevity had been elevated to a state-supported “Methuselah cult”. Robert Ripley regularly reported supercentenarian claims in Ripley’s Believe It or Not!, usually citing his own reputation as a fact-checker to claim reliability.[4
Longevity in other animals can shed light on the determinants of life expectancy in humans, especially when found in related mammals. However, important contributions to longevity research have been made by research in other species, ranging from yeast to flies to worms. In fact, some closely related species of vertebrates can have dramatically different life expectancies, demonstrating that relatively small genetic changes can have a dramatic impact on aging.
For instance, Pacific Ocean rockfishes have widely varying lifespans. The species Sebastes minor lives a mere 11 years while its cousin Sebastes aleutianus can live for more than 2 centuries. Similarly, a chameleon, Furcifer labordi, is the current record holder for shortest lifespan among tetrapods, with only 4–5 months to live. By contrast, some of its relatives, such as Furcifer pardalis, have been found to live up to 6 years.
There are studies about aging-related characteristics of and aging in long-lived animals like various turtles and plants like Ginkgo biloba trees. They have identified potentially causal protective traits and suggest many of the species have “slow or [times of] negligible senescence” (or aging). The jellyfish T. dohrnii is biologically immortal and has been studied by comparative genomics.
This increased DNA damage is likely due to an imbalance of pro- and anti-oxidants during flight-associated oxidative stress. Flight induced oxidative DNA damage appears to hasten senescence and reduce longevity in A. mellifera. In preindustrial times, deaths at young and middle age were more common than they are today. This is not due to genetics, but because of environmental factors such as disease, accidents, and malnutrition, especially since the former were not generally treatable with pre-20th-century medicine.
Deaths from childbirth were common for women, and many children did not live past infancy. In addition, most people who did attain old age were likely to die quickly from the above-mentioned untreatable health problems. Despite this, there are several examples of pre-20th-century individuals attaining lifespans of 85 years or greater, including John Adams, Cato the Elder, Thomas Hobbes, Christopher Polhem, and Michelangelo. This was also true for poorer people like peasants or laborers.
Genealogists will almost certainly find ancestors living to their 70s, 80s and even 90s several hundred years ago. For example, an 1871 census in the UK (the first of its kind, but personal data from other censuses dates back to 1841 and numerical data back to 1801) found the average male life expectancy as being 44, but if infant mortality is subtracted, males who lived to adulthood averaged 75 years.
The present life expectancy in the UK is 77 years for males and 81 for females, while the United States averages 74 for males and 80 for females. Studies have shown that black American males have the shortest lifespans of any group of people in the US, averaging only 69 years (Asian-American females average the longest). This reflects overall poorer health and greater prevalence of heart disease, obesity, diabetes, and cancer among black American men.
Women normally outlive men. Theories for this include smaller bodies that place lesser strain on the heart (women have lower rates of cardiovascular disease) and a reduced tendency to engage in physically dangerous activities. Conversely, women are more likely to participate in health-promoting activities.
The X chromosome also contains more genes related to the immune system, and women tend to mount a stronger immune response to pathogens than men.However, the idea that men have weaker immune systems due to the supposed immuno-suppressive actions of testosterone is unfounded.
Turkish scrap market debates price rise longevity
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