Helen Mirren was 61 when she won an Oscar for The Queen in 2012. Photo / AP
A new swathe of the older population making the most of their 'extra time' are a lesson to us all, says Camilla Cavendish.
Last year, a Dutchman went to court to make himself 20 years younger. Emile Ratelband, now 70, said his age was stopping him getting dates online, becausewomen did not realise that he had the body of a 40-something. He wasn't getting enough work, he argued, because of age prejudice.
He told the court he wanted to become 49, which better reflected his emotional state. The judges rejected his plea, ruling that to change his birth certificate would wreak havoc with legal rights.
But this seemingly narcissistic case illustrates something important: we need to drastically update our view of what it means to be "old".
"Why have a label?" says widow Andrea Hargreaves, 71, who has set up home with two other women her age in Sussex, southeast England, and started an arts festival.
"We are the first generation to be able to style ourselves young, and we can believe it."
In researching my book, Extra Time, I've interviewed people all over the world who are refusing to act their age. I've met sixty-somethings starting businesses, seventy-somethings changing careers, and eighty-somethings who can run and cycle further than I can.
More and more people are "unretiring" and going back to work, sometimes years after the official office send-off. These people are part of a growing group who don't see themselves as old, don't act old and won't buy products marketed at the old. It's only our expectations, and institutions, that need to catch up.
This new stage of life is called "Young-Old" by the Japanese, who are the world's longest-living society. More of its citizens will hit 100 than anywhere else. The islands of Okinawa, in particular, have so many centenarians that they are often called the "land of the immortals". Japanese gerontologists define "Young-Old" as those aged 60 to 75, or later.
Healthwise, they say, the Young-Old are completely different from 30 years ago, and they distinguish this group from the "Old-Old" - the frail elderly who need compassionate care.
Without work, things can go wrong.
"I married him for life, not for lunch," as the tongue-in-cheek expression goes, when pensioned-off husbands take over the house.
Nobuo Kurokawa, a psychiatrist, says Japanese women are suffering physical symptoms from the stress of "retired husband syndrome".
Silver divorce is soaring, partly as a consequence of couples having too much time to stare at one another.
Over-50s made up just 14 per cent of family law cases, and 60 per cent of the 369 lawyers who respondeded reported an increase in people in that age group divorcing, particularly those based in the Bay of Plenty, and the central North Island.
We rank in the top three of OECD countries when it comes to employment rates for older workers.
The annual cost of superannuation is expected to triple over 20 years, reaching $36 billion, as hundreds of thousands of baby boomers officially cross the line.
If current trends continue, some of us could spend almost a quarter of our lives in retirement. A crazy thought for those who will be healthier than any previous generation.
The first publicly-funded pension was was introduced under Richard Seddon's Liberal government in New Zealand in 1898 for over-65-year-olds. It was means-tested and the first in the world funded from general taxation.
Back then, those aged over 65 only accounted for 1.3 per cent of the population, and the male life expectancy was 54.
After various tweaks over the years the age for New Zealand's universal pension is still 65 but our life expectancy is 81.
In 2017, then-Prime Minister Bill English said the age of eligibility for NZ Superannuation would be raised to 67 by 2040.
But current PM Jacinda Ardern has promised not to alter the age of eligibility while she is prime minister, despite the Retirement Commissioner Diane Maxwell calling for the age to be increased by 2034.
Many employers are reluctant to hire or train people over 50, assuming they are dull plodders. But experiments have suggested that's not true.
When BMW put skilled workers over 50 on to one of its production lines and provided working aids such as better lighting and protection from static electricity, the results were astonishing. The older team worked faster than the younger one it had replaced.
Productivity grew by 7 per cent. Absenteeism dropped from 7 per cent to 2 per cent, below the factory average. The number of assembly defects fell to zero.
BMW and other car companies are now giving workers exoskeleton suits - metal frames with motorised muscles - which help them lift objects, and reduce injury. Such inventions are revolutionising our ability to sustain physical tasks. But the BMW story is not just about technology: it's also about belonging.
I think the Young-Old employees worked more efficiently partly because they felt like a vital part of the company's future, rather than people on their way out.
Some companies are now waking up to the fact that the retirement of baby boomers has created a skills shortage. They need older workers to fill the gaps and want employees who look more like their ageing customers.
British bank Barclays, pharmacy Boots, supermarket Co-op and insurance company Aviva have all pledged to increase the number of over-50s in their workforces by 12 per cent by 2022, and to publish data on their progress.
And with one in five over-50s now caring for an elderly relative, Aviva also offers carers generous paid and unpaid leave.
"You wouldn't hear a business saying to a pregnant woman, 'you can have the day off to have the baby, but you need to be at work the day before and the day after'," says Andy Briggs, who stepped down last week as the head of Aviva UK Insurance.
"This is the same."
Experience can often seem to count for little in a world where Facebook founder Mark Zuckerberg has proclaimed that "young people are just smarter".
Yet studies of mixed-age teams suggest that older heads can bring calm and patience to balance youthful dynamism.
Chesley "Sully" Sullenberger was 58 when he safely landed US Airways Flight 1549 in New York's Hudson river, after both its engines were knocked out by a flock of geese.
"One way of looking at this," he said afterwards, "might be that for 42 years, I've been making small, regular deposits in this bank of experience, education and training. And on January 15 [2009], the balance was sufficient that I could make a very large withdrawal."
We may need to change the type of job we do as we grow older - manual labour is likely out the door.
But those in showbiz defy working norms.
A plethora of leading ladies still dominate blockbuster films.
Dame Helen Mirren, 73, was 61 when she won an Oscar for The Queen in 2012, Meryl Streep, 69, was 62 when she won for The Iron Lady in 2012.
Dame Judi Dench 84, was in her 60s when she first played M in the James Bond franchise and Betty White, 97, continues to warm hearts on the big and small screens.
When it comes to the men, Sam Elliott, 74, was nominated for an Oscar this year for A Star is Born. Actors Sir Michael Caine, 86, Morgan Freeman, 81, Ian McKellen, 79, and Harrison Ford, 76, continue to delight on screen.
The oldest Oscar winner on record is Christopher Plummer (aka Georg von Trapp), who was 82 when he won best Supporting Actor for Beginners in 2010.
And Clint Eastwood is the oldest director to have won. He was 74 when he took home the gong for Million Dollar Baby.
The happiest, most vibrant older people I have met have a strong sense of purpose. In Okinawa, where there is a much lower incidence of stroke and dementia than in the West, they talk about ikigai, which translates as "reason for being". Ikigai is the guiding philosophy of Japan's Silver Centres, which find part-time work for the Young-Old.
"It gives me a bright mind," says 98-year-old Shuize Ohata, the oldest of a group of wizened ladies at the Edogawa Silver Centre, Tokyo.
The women are sitting around a table, wearing flowery aprons they sewed themselves and tying gold ribbons round parcels. It's a fiddly business, which saves the local factory time. The Silver Centres are a blend of work and coffee mornings: tea parties with purpose.
"Ninety-three per cent of our members are very healthy," Edogawa's director told me.
"We believe that our system helps keep them that way."
So how can we make the most of our own "extra time"?
We need to plan longer careers and be far more optimistic about what life can hold. We need to stop portraying dementia as inevitable (in the UK, it has fallen by a fifth over the past 20 years) and utilise research that shows how our brain cells continue to develop throughout our lives.
We need to knit the generations back together and recruit older people to help tackle some of society's most urgent tasks: like conserving nature.
We will also need to revolutionise our attitudes towards health. One group of Americans who took up jogging when it became a craze in the 1970s, and continued to jog, cycle or do other regular exercise for the next 50 years, were found to be biologically 30 years younger than their chronological age.
Almost every scientist I've interviewed takes exercise seriously, and is careful about what they eat. Some are working on anti-ageing compounds, which will come to market soon. These won't let us off the hook of eating right and exercising – and they won't abolish bad luck - but they will, I believe, make more of us younger for longer.
So instead of going to court to change our birth certificates, let's change our notion of "old" to Young-Old. You may be younger than you think.
• Extra Time: 10 Lessons for an Ageing World, by Camilla Cavendish, is published by Harper Collins, RRP £20.
Tips to help you live longer
Sleep This is the most important factor for our health. Most people need a good eight hours a night. If we don't get our sleep right then it is very difficult to get get anything else right.
Brain activities The brain is best seen as a muscle: if we don't use it, we lose it. Stress, lack of sleep and ageing all break brain tissue down. However, the brain is elastic and every time we practice something, we rebuild that part of it. We should do as many activities a day as possible to stimulate our grey matter: reading, crosswords, balancing, kicking a ball, dancing, swimming, singing, drawing, speaking another language. The older we are, the more we should make this a daily habit.
Exercise Twenty minutes of intense exercise that combines weights, balance and endurance is optimal and will help stave off heart attacks, and diabetes. It will also stimulate brain development, boost the immune system, reduce stress and anxiety, and clear toxins.
Nutrition Processed foods and sugars are bad for us: margarines, canned vegetables, canned tuna, ketchup, mayonnaise and soda drinks. For many years we had a blind spot for sugar, but the world has woken up to this toxin and governments are slowly putting pressure on industry to remove it.
Supplements Antioxidants like vitamin C and vitamin E are no longer recommended in high doses. They may slow down our own powerful antioxidant systems, doing more harm than good. High quality fish oil and vitamin D have many benefits. But if I were to take just one supplement it would be a good quality multivitamin, three times a week. We don't need it every day, but a Solar or Metagenics a few times a week should replace the minerals and vitamins we are not getting from our modern nutrient-poor diet.
Laugh In 2017, Japanese physician Dr Shigeaki Hinohara died aged 105. He championed the concept that we should never retire, but continue working for society - as he did until a few months before his death at 105. He was a fan of physical activity and even after the age of 100 encouraged people to climb two steps at a time. But the topic that he was fascinated with was laughter - a powerful healer, important painkiller and essential part of living younger.