How long can humans live? This is a question that has fascinated scientists and laypeople alike for centuries. While average life expectancy has increased significantly over the past century, thanks to improved sanitation, medicine and lifestyle, there is still much debate about whether there is a limit to human lifespan and what that limit might be.
Some researchers believe that human lifespan is essentially programmed by our genes and evolution, and that there is a hard limit of around 115 years. This is based on the observation that the oldest verified human, Jeanne Calment, died at 122 years in 1997, and that the age of the oldest person alive has not increased much since then.
These researchers argue that aging is a natural process that cannot be reversed or stopped, and that our cells and organs eventually wear out and fail.
However, other researchers challenge this view and suggest that human lifespan could be extended much further, even beyond 1,000 years. They point to the fact that some animals, such as the bowhead whale and the naked mole rat, can live for over 200 years, and that some species, such as the hydra and the jellyfish, seem to be immortal.
They also note that aging is not a uniform phenomenon, and that different tissues and organs age at different rates. They propose that aging is caused by molecular damage and errors that accumulate over time, and that these could be prevented or repaired by manipulating genes, drugs or other interventions.
One of the most prominent advocates of this view is João Pedro de Magalhães, a professor of molecular biogerontology at the University of Birmingham in England. He has studied the genomes of long-lived animals and humans, and identified genes that are involved in aging and longevity.
He believes that if we could eliminate aging at the cellular level, humans could live for a millennium or more (possibly even as much as 20,000 years). He compares aging to a disease that can be cured, just like infections were cured by penicillin in the past. He says he wants to “cheat death” and extend human lifespan indefinitely.
“I actually did some calculations years ago and found that if we could ‘cure’ human aging, average human life span would be more than 1,000 years,” Magalhães told Scientific American.
“Maximum life span, barring accidents and violent death, could be as long as 20,000 years.”
“This may sound like a lot, but some species can already live hundreds of years—and in some cases thousands of years.”
However, this is not an easy task. Aging is a complex and multifactorial process that involves many genes, pathways and environmental factors. There is no single magic bullet that can stop or reverse aging in all cells and tissues.
“Is it going to happen soon? I think it’s quite unlikely. Even if you can figure out how aging works, it is not easy to develop interventions,” Magalhães says.
“I am an aspiring science-fiction writer as well, and one thing I’ve noticed are these novels that are set 100 or 1,000 years from now, in a future with all kinds of technology that enables people to do incredible things, such as travel between stars—and people are still aging. But I think we’ll figure out aging by then.”
Moreover, there are potential risks and ethical issues associated with extending human lifespan beyond natural limits. For example, how would it affect population growth, resource consumption, social structure and human identity?
Would it create inequalities and conflicts between those who can afford to live longer and those who cannot? Would it diminish the value and meaning of life?
These are some of the questions that need to be addressed before we can decide whether we want to pursue extreme longevity or not.
For now, most scientists agree that we can improve our health span, which is the period of life free of disease and disability, by adopting healthy habits such as eating well, exercising regularly, avoiding smoking and stress, and having social support. These factors can help us live longer and better, without necessarily reaching the limits of human lifespan.