As 75-year-old John Cotter laced up his running shoes for last October's Dublin City Marathon, many younger runners looked admiringly at what they presumed was a seasoned veteran. Little did they realise this was the Galway man's first attempt at running 26.2 miles.
And after six-and-a-half hours pounding the pavements of Dublin city and its suburbs, John had finally achieved what many people thought he was far too old to – he had just ran his first marathon.
However, completing the marathon was nothing compared to the satisfaction John received hearing his grandchildren – who had travelled from their homes in Galway, Wicklow and Dublin – cheer him on.
"They had made T-shirts and banners, which they had placed around the course," says John. "And it was great to show off the medal once I got my hands on it!"
Now 76 years of age, John is still running and recently took part in the Meath Cross Country Championships on October 6, representing the Fit4life programme at Dunboyne Athletics Club, of which he is a member. He is not sure if he has another marathon left in him, but he has no plans to hang up his running shoes.
"I plan to keep doing races up to about 10 miles or so," he says. "And my advice for people of my age is not to be sitting in a chair. It is important to get out and do something. You need to challenge yourself in whatever capacity you can, which will not only help your aerobic health but also your mental health."
But even though John was rightly proud of his achievement, he is just one of a growing number of runners not letting age stand in their way when it comes to completing one of the sporting world's most gruelling races.
In fact, runners aged 50 years and older represent one of the fastest-growing age groups participating in marathon events around the globe – and they no doubt take inspiration from the words of the Czech long-distance runner Emile Zatopek – "If you want to run, run a mile. If you want to experience a different life, run a marathon."
The total number of runners finishing marathons in the US doubled to 518,000 in the 20 years up to 2011, whereas the number of finishers age 50 and older nearly tripled to 92,200, or about 18pc of the total, according to Running USA, an industry-funded research group.
And while many like John choose to run their first marathon, others like Tommy Hughes from Derry do not let age blunt passion for the long distance run.
In 1992, the Derry man ran his personal best of 2 hours 13 minutes in the Marrakesh Marathon and later in the year represented Ireland at the Barcelona Olympics. In 2011, aged 50, Tommy defied his age and ran 2 hours 29 minutes to win the Robin Hood Marathon in Nottingham.
Nevertheless, regardless of your date of birth, running 26.2 miles is a punishing pursuit. And the stresses of long distance running are harder on ageing joints, feet, muscles and backs. This leaves older marathoners much more prone to injury than younger competitors.
To reduce injury risk for older people, coaches recommend more stretching, including light yoga, and more rest and recovery, particularly after the long training runs that are the staple of any marathon-preparation program.
However, research has shown that running marathons is safe for older adults. Tests carried out at the University of Manitoba in Canada on marathon participants over age 50, before and up to three months after their 26.2-mile run, found they did not differ in terms of health affects from runners aged 18 to 40.
In fact, there is a growing body of evidence that shows running can reduce the risk or delay the onset of cardiovascular disease, dementia, cancer, depression and other diseases – all of which are big concerns for many as they get older.
And compared to their younger counterparts, those who are a little more advanced in years are also more likely to have the free time needed to spend long hours training and the ability to afford the costs of race entry fees, coaching, running equipment and possible travel expenses to races.
But while the numbers of over-50s running the Dublin marathon this year was at an all-time high, it appears there is a limit to how long runners can continue to defy age. And so, even though he is an inspiration to many, the world's oldest marathon runner is due to call time on marathons after competing in next month's Hong Kong Marathon. So, India-born Fauja Singh (left), who is now a British national, will no longer be signing up for races once he crosses the finish line.
But then again, he is 102 years old. What's your excuse?