As a young reporter in the 1980s one of my first assignments was to interview a retiring coal miner who had worked in the earth’s dark underbelly for more than 40 years.

At the age of 18, the idea of 40 years seemed like an eternity to me, and I asked how he had endured for so long.

“It really doesn’t feel like 40 years,” he confessed. “In fact, it only seems like yesterday that I was your age. And inside my head I really don’t feel any different than I did then.”

For some reason those words have always stuck with me and, as I get older, the truism of life’s unrelenting time march becomes even more pronounced.

But, in the 30-odd years since that interview, things have changed. Back then, an Australian male could expect to live about five years after a standard retirement. Today, based on the same retirement age, a large proportion of the population are on track to be retired for as many years as they worked.

Around the world, governments are pushing back the official retirement age. The very thought messes with our sense of entitlement in countries where paying taxes and working hard are synonymous with earning the right to comfortable, largely government-funded twilight years.

However, as the following points reveal, this is a debate that we will need to bring on.

Old age is a relatively new phenomenon

Researcher and author Fred Pearce (Peoplequake) says it is quite possible that half of all the human beings who have ever lived past the age of 65 are alive today. The rules of demography and longevity have changed, and only recently.

Working longer and living to really advanced years often go hand in hand. In 1958, polling agency Gallup discovered that, for men who lived to the age of 95 and beyond, the average retirement age was 80.

But these men were not just working for the sake of it. Whether they were collecting supermarket trollies for a living or doing office filing, they liked what they did and found it engaging and meaningful.

Sometimes old age is a mindset imposed by social norms

In his brilliant book, Before Happiness, Shawn Achor cites a 1979 study by Harvard psychologist Ellen Langer in which she was able to reverse the effects of ageing on a group of 75-year-old men by having them pretend they were 20 years younger.

Basically, Langer took her subjects from a nursing home environment with cafeteria meals, scheduled recreation and a community of mostly elderly strangers and took them back to the world of 1959. She did this by using a converted monastery to recreate the clothes, music, television, books and magazines of the era.

Instead of reminiscing about the past, they were living it again. And nobody treated them as old people. By the end of the experiment, the majority of the group had improved physical strength, posture, memory, and cognitive function. The experiment largely backed the notion that you are only as old as you act.

Living past 100 is becoming much more common

It is now clear that growing numbers of people will live past 100, something unthinkable a century ago. This will fundamentally change the type of lives we live.

According to The 100-Year Life by Lynda Gratton and Andrew Scott a child born in the West today has a greater than 50 percent chance of living past 105.

The same book relates that Japan used to give a silver sake dish to everyone who turned 100 in that country. In 1963 it was given to 153 people. By 2014 the number had grown to 29,350, and it was discontinued a year later.

Similarly, the Queen of England has long written to anyone who turns 100 in the Commonwealth. Over the single decade, the number of people administering these cards rose from one to seven.

Stressful jobs and long life sometimes happen together

There is a common myth that stressful jobs lead to early deaths. This is not necessarily so. American presidents are a good case in point. A 2011 study by Chicago demographer S. Jay Olshansky found presidents generally lived longer than expected for men of the same age and era. In fact, 23 of the 34 US presidents who died from natural causes lived longer than statistically expected.

The average lifespan of the first eight presidents was 79.8 years at a time when the life expectancy for the average man was 40! Modern presidents have also enjoyed long lives. Ronald Reagan and Gerald Ford both lived to 93. George HW Bush lived to 94. Jimmy Carter has lived even longer.

The election of Joe Biden to the Presidency at 78 will help to reset perceptions around age. There is something inherently inconsistent between the willingness to elect someone of that age to one of the most demanding jobs in the world, and the expectation that workers will move out of paid work in their sixties.

What does this mean?

The long life of many world leaders highlights one of the key lessons about ageing and retirement. Clearly wealth, privilege and access to top medical care can extend your life no matter how stressful some of your jobs are.

It is also clear that there are jobs, and jobs. Mentally stimulating jobs performed in a climate of general good health, proper eating, genetic luck, physical activity and supportive friends and family don’t seem to have a use-by date.

But who would begrudge the man I interviewed 30-odd years ago having a comfortable retirement at 65 after so many years of physical work in dark and dusty coal mines?

At a time when skills and labour shortages are at historical highs, older workers who genuinely want to stay in the workforce are a valuable asset. We will only make proper use of this asset when we value it and get past a use-by mentality for people with experience and energy.

Shane Rodgers is a business executive, writer, strategist and marketer with a deep interest in what makes people tick and the drivers of change. Comments in this article are personal and not related to my day job.