In 1997 on August 4, a French woman, Jeanne Calment died aged 122 years old. She was the oldest verified human being in history, and new scientific research indicates her record may never be broken.
Life expectancies have been rising rapidly in mankind’s recent history. In 1900, the average age someone could hope to achieve was about 50. But thanks to a string of medical breakthroughs concerning common killers such as smallpox and polio, in addition to better diets, improved sanitation, and clean drinking water, the average British person can expect to live to 81 or more. As medical science improves still further, this average seems set to climb still higher.
However, this trend cannot continue forever. A report published by the Albert Einstein College of Medicine in New York contends that, while average life expectancies may still increase, the maximum possible lifespan of a human will likely never exceed 125 years of age. While vastly improved medical care has ensured that ever-increasing numbers of people are reaching their 100th birthday, there is only a finite number of times a cell population can divide before the process begins to break down, and for this degeneration in cell division, science has no answer.
The bodies chromosomes are protected by a sturdy cap called a telomere, which prevents the chromosomes for degenerating, and thus protecting the integrity of the vital DNA strands. But as your bodies cells divide and split, the telomeres gradually wear away, until they shorten so much that cell division becomes unstable, leading to deadly cancers, or becomes entirely impossible. This upper limit to human cell division is known as the Heyflick Limit, and the scientist who coined the term, Leonard Heyflick, used it to calculate that no human would live beyond 120 years of age. Although Jeanne Calment beat his calculation by two years, it does nevertheless suggest she was at the very limit of what is humanly possible.
Dr Jan Vijg, a professor of genetics at Albert Einstein, stated that: “Further progress against infectious and chronic diseases may continue boosting average life expectancy, but not maximum lifespan”. He suggested that “resources now being spent to increase lifespan should instead go to lengthening healthspan—the duration of the old age spent in good health”.
Yet some scientists content that while 125 years may be the natural limit imposed by cell division, these problems may not be insurmountable through scientific advances, potentially allowing humans to live far beyond their natural limits.
Professor David Sinclair, of Harvard University, said: “New technologies to enhance our body’s defences against ageing have been made in labs throughout the world that could break through this apparent limit to human lifespan.”
– Greg Taylor, Correspondent (Science)