Runners half Blanche Moila's age cannot keep up with her when she hits the road, even when she's just completed a 12-hour night shift as a psychiatric nursing sister. Moila, 63 ("and five months!" she insists), may no longer run at the speed that made her the first black female athlete to get national colours, but in all other ways she hasn't slowed down a bit.
"I'm not as regimented as I used to be, but I do run daily," says Moila, who coaches children in cross-country running in her spare time and will be running her 15th Comrades Marathon next month.
Moila exemplifies the category of people once dismissed as over the hill who are actually still in their prime. Dubbed the "young-olds" in Japan, these over-60s defy the limits and stereotypes of ageing, and you don't have to look far to find them in SA.
Rock climber Errol Flint, 69, is physically and mentally strong. In the 1960s he was climbing on Table Mountain when it was a far riskier sport and he can still be found hanging off its cliffs every weekend.
"Age is just a number," says Flint, who still works part-time and keeps his mind as agile as his muscles. He is no tech dinosaur, using platforms like Pinterest to inspire projects rather than "sitting around doing nothing". That's where he got the idea to turn his old climbing ropes into a carpet.
Cape Town neurosurgeon Dr Roger Melvill, 78, attributes his robust health and extended career to his genes, being mentally active and never smoking. He was a hobbyist mountaineer until he decided to devote the spare time not taken up by his 11 Siberian huskies to painting. Not long ago he accompanied polar swimmer Lewis Pugh to Antarctica, joining the expedition as official doctor and artist.
"I do neurosurgery from Monday to Friday," he says, "but I'm really working as an artist."
Jazz maestro Abdullah Ibrahim, 85, still undertakes arduous world tours, performing day and night. He attributes some of his energy to a Japanese physical discipline involving breathing and movement.
"It is based on respecting and embracing nature: water, flowers, mountains, animals," says Ibrahim. "It also stresses the absolute importance of being aware of what we eat and drink."
These stalwarts are living proof of how old age is being pushed further back every day, thanks to a combination of better nutrition, activity, knowledge and enlightened attitudes.
This phenomenon is seen all over the world. "Much of what we previously thought of as inevitable in ageing is in fact preventable," says Professor Janet Lord, director of the Medawar Centre for Healthy Ageing Research in the UK.
A person's "biological age", measured by health indicators, can be decades younger than their actual age in years. Physical activity is still the biggest factor in keeping the body and immune system young, as Lord's studies have proved.
"We know exercise affects all parts of the body," she says, "so by keeping active you are taking a medicine that has a universal benefit. It is never too late to become more active. Lots of research has shown that you can reverse some of the bad aspects of ageing by taking a brisk daily walk."
The battle against ageing is leaping forward on other fronts, such as gene-based therapy.
Dr Alexandre Benedetto, a biomedical scientist at Lancaster University in the UK, says: "For decades scientists studying ageing have thought of ageing bodies as wearing out, much like cars do, from a build-up of damage.
"It turns out that we are not like cars. What kills us when we're old is not random damage, but our own genes."
Camilla Cavendish, author of Extra Time: 10 Lessons for an Ageing World, says there are astonishing breakthroughs being made in understanding the genes that affect the way we age.
"One of the reasons we age is that our DNA is progressively damaged," she says. "I'm convinced we will see drugs coming to the market that may help the process of repairing DNA." Such drugs are already being tested in clinical trials globally.
Until we have access to gene-repair mechanisms, physical activity and good nutrition remain the most reliable bulwarks against decline.
There is no formula for healthy ageing, says Cavendish, but while conducting research around the world she found that having a purpose, a sense of community and an optimistic outlook are as vital as food and exercise.
Nonkosi Sontshatsha, 76, has all three of these by the bucketful and is spreading them around. She has formed a seniors' club in Gugulethu that offers aerobics classes at the community centre and swimming at the gym in summer. Some of her members compete in SA's annual Golden Games.
"I have helped to plant and harvest vegetables for people who can't afford them," says Sontshatsha, who has six children and 13 grandchildren and has been married for 45 years. She was chair of her local branch of the South African National Civic Organisation and is still involved in street and ward committees.
Strong social and family connections are another facet shared by the young-olds.
This is something future generations may struggle with, as Cavendish notes: "What we are losing in this anonymous world is that social connection," she says. "We don't need a lot of friends, just a couple of close ones who we can rely on and who can rely on us - people who feel needed and useful live longer and healthier lives than people who don't."
Pushing back the onset of ageing comes along with the ability (and the economic need) to work beyond traditional retirement age, and this is beginning to be recognised by some global industries.
Automation and artificial intelligence can improve quality of life for the aged as well as extend their value says Cavendish.
She cites an experiment in which older workers at a BMW plant were provided with exoskeleton suits (with motorised muscles) to help them perform their tasks.
Not only did productivity grow, there were zero assembly defects on this production line. Cavendish suggests this wasn't only due to robotic assistance but to the positive effects of making older people feel included, appreciated and part of a team.
She calls the ability to live a better, longer life our "extended middle age" or our "extra time". The aim is not simply to live to 120 but to reduce senescence, to compress the last part of life during which we decline to as narrow a slice as possible.
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