What is the secret to a long and contented life? It's easy to think it's all down to genes – the biological luck of the draw. This is partly true, of course, and some are born with a much greater chance of reaching a ripe old age than others. But genes aren't the only factor at play. During the course of my career, I've come across elderly people who seem to defy the ageing process. Of course, they get ill like the rest of us mortals, have wrinkles and aching joints, yet there is something about them that sets them apart. They seem to have an ageless, youthful quality.

One of these pensioners, Dennis, turned 100 recently. Happy Birthday Dennis! He reads this column every week and emails me regularly. Indeed, he's a fascinating correspondent, full of interest in politics and culture, sparky, alert and fully up to date on news and current affairs. Yes, Dennis has health problems from time to time, but there is a relentless joie de vivre about him that is writ large in our correspondence.

For people like Dennis, while their years may be advanced, age really is just a number. According to Professor Emily Rogalski super agers have a 'unique personality profile, highlighting optimism, resilience and perseverance'. Scientists have increasingly started studying these elderly types, dubbed the 'super agers' because of their apparent resilience to the passing years. Why are they so much better at ageing than the rest of us, and, if so, can we harness it as some kind of longevity elixir?.

In my experience, a good part of this is about mindset. What I've learned from observing these healthy, vibrant elders is that –regardless of genetics – they all seem to share certain common attitudes and behaviours. And they're not just physical but also psychological. According to Professor Emily Rogalski, of the University of Chicago, who has studied this group extensively, super agers have a 'unique personality profile, highlighting optimism, resilience and perseverance'. Crucially, they also have an active lifestyle.

While there may be no sure-fire way of becoming a sprightly centenarian, here are the top take-away life skills – and the mental outlook – that my super-ager patients have taught me... When I ask elderly people about their lives, careers are rarely mentioned. Instead, the talk is of hobbies and interests they're still passionate about. Rates of death and ill health peak shortly after retirement, and I think that's because many people are left bereft by their loss of status. The job that once defined them has gone, and the loss of this part of their identity puts the body and mind under considerable strain.

The takeaway is, have a job you enjoy but do not make it your sole focus. It always amuses me that most fit and healthy-looking pensioners say no when asked if they exercise – only to then say, for instance, that they swim daily, or walk the dog, or play golf. Also known as exercise!. The key is they never think of it as exercise. The trick is finding a form of movement you love and keep doing it as often as you can.

There will always be someone who earns more, has a bigger house, and so on. But the comparison game will only make you bitter, resentful and unhappy. Super agers don't fall into this trap. They have a relaxed approach to life, happy for others but also content with their lot. Super agers are always on the go and get out of the house as often as possible. Far better to drink tea in a cafe or read a book in a library than do it at home.

Meeting people, connecting, learning and engaging with the world outside your front door will help keep your mind fit and agile. Super agers are open to new experiences. One 80-plus friend of mine has a far busier social life than me and tells me her mantra is to say 'yes' as often as possible. 'When you say yes, you can always change your mind,' she says. 'But, if you say 'no', you've closed that path down for good.'.

Every super ager I know has friends from all walks of life and all ages. You'll often get on better with a 20-year-old who shares the same passions as you than someone your age where the only thing you have in common is your date of birth. I've never, ever met a dowdy or badly dressed super ager. In fact, Dennis often sends me snaps of the snazzy jumpers he's wearing. OK, so only the residents and staff at his care home will see them, but who cares?.

Be more like Dennis and you'll feel more confident and ready to take on new challenges. The one trait every super ager I know shares is a positive mental attitude. I've never met a red-faced and angry 90-year-old. While we can't do anything about our genes, we can take a leaf out of the sunny super ager's book and adopt a more positive attitude. Stress is a killer for all sorts of reasons and a tendency to look on the bright side is the best weapon against it.