"Over the years I've done most of the Round the Bays, but have walked it for the last 10 years or so because of minor surgery on both knees."
He says the key to staying injury-free and active is regular exercise and a good osteopath. He is sure his friends and family shake their heads at his ongoing sporting endeavours.
"They probably think 'silly old bugger' [laughs]. I like to think they are pleased and proud that I'm still participating and perhaps setting an example for others to follow."
He said there was a lot to love about hitting the trails.
"It is experiencing New Zealand's outdoors and exercising.
"I love seeing families ... participating, and applying the competitive streak in me."
His competitive streak is still as keen as ever.
"After each event I have a sense of enjoyment, satisfaction, and perhaps had I pushed a bit harder I could have done better. I've got no time goals [for the short series in 2013], perhaps I am setting targets to beat next year."
He said his age did not come up in conversation with his fellow competitors but he "found all of the participants to be friendly - before, during, and after the event".
Beatson doesn't train these days. He walks to work (about 4.5km) and has a few basic exercises that he performs at home.
"Our managing director, Naomi Ballantyne, of Partners Life [one of the Xterra Series sponsors] arranged for a fitness instructor to visit us each week to conduct a boot camp session on Takapuna Beach and provide advice to individuals as required, which has been good."
He has some simple advice of his own for other older athletes who are struggling to stay fit.
"Moderate exercise regularly, listen to your body and get good advice. I no longer run because of knee problems but I will continue to participate for as long as my body will let me."
Xterra Auckland
Blackmores Xterra Auckland trail run/walk series
Event 6: Hunua Ranges - Sunday, September 1
Event options:
* Short (5-8km) walk or run
* Mid (10-14km) walk or run
* Long (16-20km) run only
* Super-long (20km+) run only
For more information visit: www.trailrun.co.nz