Scientists have revealed the oldest possible age a human could live to be, according to new research. Data from the Office for National Statistics puts the average life expectancy for men in the UK at 79.9 years and 83.0 for women, but researchers from the Skolkovo Institute of Science and Technology in Russia reckon the ultimate limit of the human lifespan is an astonishing 190 years.
Why 190 years?
The experts discovered that as we get older, we are subjected to a build-up of random mutations in our DNA. At a basic biological level these range from the shortening of 'caps' on our DNA strands called telomeres, through to our cells losing their ability to clear waste from our bodies. However, what scientists looked at in closer detail was tiny mistakes known as 'somatic mutations' which appear in our DNA whenever a cell divides. Most of these are harmless but can occasionally give rise to changes which cause cancer. The build-up of somatic mutations over time eventually begins to impair how cells function, leading to organ failure and eventually death.
Model of human ageing
Lead author Dr Dmitrii Krukov asked: 'What would be the lifespan of a human who has overcome all ageing mechanisms except somatic mutations?' To find out, the experts built a model of human ageing driven solely by these mutations. 'Our model estimates how this process alone affects lifespan by slowly depleting cells across tissues,' Dr Krukov explained. 'If medicine could treat everything besides these somatic mutations, average lifespans range between 146 and 194 years old, depending on the exact model used. It’s not a verdict of inevitability. But it does highlight that somatic mutations, while surprisingly weak as a standalone ageing driver, may become critical when combined with other mechanisms.'
That doesn't mean that humans will start living for 190 years any time soon, as certain organs are more successful at beating ageing than others. The research found, for example, that cells in the skin and the liver are continually replaced with new ones, so can keep going for longer, while those in the heart and the brain are largely irreplaceable, so will continue to gain mutations regardless.
