Humans have in-built time limit, says study

Happy 120th!: Jeanne Calment celebrates her birthday. © Jean-Paul Pelissier

For decades, people in the developed world have enjoyed ever longer lives. But according to new research, we may soon hit a natural limit of 115 years. Can we change that? Should we?

As a girl she met Vincent van Gogh. In her later years she produced a rap album. When Jeanne Calment died in 1997 at the age of 122, she set a record for the longest ever lifespan. According to a new study it could stand for a long time.

Researchers have found that people in the developed world tend to live longer once they hit 70 than they did a century ago. For over-100s, however, there has been far less improvement. The study concludes that humans have a maximum lifespan of around 115 years. Even with all the medical treatment in the world, our genes are unlikely to let us live beyond that.

The brevity of life has always fascinated us. Ancient texts are peopled with characters who defy death, from the Bible’s 969-year-old Methuselah to the family of bickering gods in Homer. For most of our history we interpreted extended life through religious concepts like the afterlife — it was not a literal goal.

In the 20th century that changed. Medicine made rapid progress: the average lifespan of a first-world citizen shot up from 47 in 1900 to 80 in 2016. The science of ageing developed. Experts began to talk of ‘Methuselah genes’, which determine our lifespans. This prompted the question: what if we could change our genes?

Some refuse to accept the idea of a ‘lifespan limit’ – and are spending big money to prove their point. Google has opened Calico, a mysterious lab specialising in longevity research. A Silicon Valley entrepreneur has set up the Palo Alto Prize, offering $1m to anyone who can ‘hack the code’ — that is, our genes. Dozens of teams have applied.

The exact mechanics of ageing remain unclear, and researchers are studying it from all different angles. But they are united by one belief: rather than invest in cures for specific diseases, we should focus on delaying old age. This will lead to healthier, longer lives — even (whisper it) immortality.

Yet as this field has grown, so have the ethical concerns around it. Those in the field are often called ‘optimists’, as if longer lifespans are unarguably good. But not everyone agrees…

The good young days

Ageing is not a disease, say some. It is what gives life meaning. Our in-built expiry date spurs us on to achieve things and enjoy each day. Homer’s gods may be energetic and beautiful, but they lead a frivolous existence. Practical problems aside, extending our lifespan would undermine our very humanity.

Hang on, reply others. Our lifespans are almost double those of our great-grandparents, yet we are no more depressed or frivolous than they were. As our lives get longer, our capacity to fill them with meaning grows. Think of the things we could achieve, the places we could visit, if we had centuries…

You Decide

  1. If you could live forever, would you want to?
  2. At what point does one’s youth end?

Activities

  1. Imagine you lived until 1,000. Come up with five goals you would set yourself (which you otherwise could not achieve).
  2. Take the Life Expectancy Calculator test in Become An Expert. How well designed was the test? Did it leave any crucial factors out? Write down your thoughts in 500 words.

Some People Say...

“Youth has no age.”

Pablo Picasso

What do you think?

Q & A

How long will I live?
You know we can’t answer that. Scientists agree that lifespan is shaped by a blend of genetic factors such as a family history of heart failure, others we control like the amount of exercise we do, and environmental ones. But they don’t agree on the balance between them. If you want a very rough estimate, take the test in Become An Expert.
Why do women live longer than men?
For ages, people put this down to differences in lifestyle: men did the harder work, smoked more, etc. But evidence shows that the age gap remains even as these differences shrink. So scientists have turned to biology. Some have suggested that testosterone leaves men vulnerable to various illnesses; others, that the XX chromosome defends women against cellular malfunction. But nobody is quite sure.

Word Watch

Jeanne Calment
The Frenchwoman put her incredibly good health down to her large consumption of olive oil. She drank wine and smoked until she was 120.
Longest ever
Calment has the longest confirmed lifespan – others have claimed ages beyond 150. Of the 100 (confirmed) oldest people in history, 94 were women.
Researchers
From the Albert Einstein College of Medicine in New York.
Methuselah
According to Biblical scholars, Methuselah died in the flood sent by God to test his grandson Noah.
Homer
A legendary Greek poet uncertainly reputed to have lived in the 8th century BC and to have composed the two epic poems The Iliad and The Odyssey, both towering classics of Western literature.
All different angles
Some are focusing on genetic engineering, while others believe that injecting the body with certain chemical compounds is the answer. At the moment, most testing is being carried out on animals.
Healthier
In recent years scientists have begun to talk of ‘healthspans’, ie, the period of life spent in good health. Of course, a longer healthspan will generally lead to a longer lifespan.