![]() After that, nature becomes indifferent and you are left to the capricious ravages of entropy. ![]() Our selfish genes are under evolutionary pressure to maximize their own propagation - which means you’re programmed to live long enough to care for your offspring until they are reasonably self-sufficient. He says it’s important to understand that we’re not programmed to die at a certain age. Jay Olshansky, an expert on aging from the University of Chicago. It tends to be the long-lived, slow-to-reproduce animals that are more vulnerable to extinction. Moreover, Mayne explains, the aging clocks of animals are tied to their reproductive clocks. DNA of different species varies in the number of sites prone to methylation - the more sites, the faster the aging clock ticks. Over time, our cells accumulate methylation much the way our arteries pick up plaque or our teeth start to decay. It doesn’t affect the actual code, though it affects how the code is read and expressed. Mayne, who works at the Commonwealth Scientific and Industrial Research Organization in Australia, says that his system relies on a well-known marker of aging called DNA methylation - a change in the material that gloms onto your DNA. Even agriculture seems to have been a mixed blessing: Medical archaeologists have found that compared to their foraging ancestors, ancient people from farming societies were shorter and more likely to be diseased or undernourished.ĭr. The diseases that kill most people over 55 are heart disease and cancer, both of which, we are told, would be less rampant if people got more exercise, avoided cigarettes and ate less processed food, sugar and high fructose corn syrup. People who survived the dangers of childhood were pretty likely to live to a ripe old age.Īlso read: Superstar cities are witnessing domestic exodus & possibly entering a new phaseĪnd modern life seems to be as much a killer as a savior. Life expectancy was just 46 in 1907, but that was because it was routine for kids to die – not because anyone died of old age at 46. Before modern medicine, infants and children often did die from infections, malnutrition, or birth defects, and newborns as well as young women died from childbirth complications. Remember, life expectancy is an average, and for centuries it included a disproportionate number of infants. People sometimes confuse death from old age with life expectancy, which was quite low for humans for a very long time. ![]() Historical records show that the pace of human aging has been the same for 2,000 years. Benjamin Franklin, who had pointed out that 18th century medicine did more harm than good, managed to live to 84. Socrates was 70 when he died, and was still so vigorous that his enemies had to do him in with poison. Captive chimps with good healthcare don’t ever live to 80 or beyond, while people routinely do - and did so long before there was anything like modern medicine. But still, it doesn’t square with observations. ![]() So if we have a record of 120, and “true global average” of 61-86, how could we have a natural lifespan of 38? In some ways, that number makes sense, given that our closest relative, the chimpanzee, lives to 37 years. According to the paper, which was published in Nature Scientific Reports, “this does not reflect the variability the true global average lifespan (60.9–86.3 years).” Humans have a maximum known lifespan of about 120 years, but this was excluded from their calibration data for being too much of an outlier. The researchers calibrated their aging clock using animals that have been kept in captivity and whose maximum lifespans are recorded in a database. The 38-year limit comes from a system Mayne and his colleagues created to apply across vertebrates, from the live-fast-die-young forest shrew (2.1 years) to the slow-lane Greenland shark (400 years). ![]()
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