It takes a certain brand of fortitude to be an Ironman, the long-distance variety of triathlon that is only for the foolish or the brave.

The parting, however, will be a test of resolve. “The last two years I’ve gone to South Africa, I’ve flown out well before the Christmas tree’s up and the decorations,” he reveals. “It will be hard being away. Really hard.”

If only Santa did plane tickets, it might not be this way. Instead, the 27-year-old has had to take the cheapest airfare available to reach his winter training camp, regardless of date or sentiment. “A no-brainer,” he concedes.

Despite regularly placing in the top 10 in races on the world half-Ironman 70.2-mile circuit over the past two years, his budget does not afford frivolity. And with funding available only for those triathletes competing at the (shorter) Olympic distance, the pay is strictly performance-related.

With a degree in civil engineering stashed away, the Scot admits he would have been better off with a “proper” job. Britain’s elite performers are hugely successful but they soak up the spoils.

“Triathlon has boomed hugely in the UK the last few seasons. Alistair Brownlee’s done fantastically well winning the world title and we’ve got a host of other people around. But that was the catalyst for me moving away from Olympic distance racing.”

Like his compatriots, and fellow Ironman specialists, Catriona Morrison and Bella Comerford, Cartmell consciously opted out of the Olympic pathway. “I never had the run speed,” he appraises. “I maybe hoped to make a Commonwealth Games. If I’d really been keen I might have stuck around. But the emphasis here is on that distance.

“They’re desperate to win an Olympic medal in 2012, given that Britain has never won one despite the fact we’ve had a clear medal favourite at every Games since it was introduced. That’s the way it goes. It’s just on the day. But it means that every other kind of triathlon – duathlon or Ironman – just isn’t given the same support.”

The family coffers have been generous, he reveals. Plus there has been logistical help from within his base at Stirling Tri Club. In recent weeks, his training has had to circumvent Scotland’s natural elements on top.

With a weekly regime that incorporates around 25 kilometres in the pool, 600k on the bike and 100k running, the option to stay indoors and spend his days supping mulled wine has not been available. Switching hemispheres is not a choice but a necessity.

“I’m very fortunate that I get to train in warm climates and do what’s required there alongside the best in the world,” he underlined. “You need to be able to do it consistently, which is why it’s not really possible in Scotland. Particularly on the bike, it’s not safe on the roads in the winter-time with the lack of daylight hours.

“I’ve tried the past two years but I really need to get out to South Africa. There are races there in January so I can justify putting in a block of training there in their summer and hope to get a result out of it. Same with America, later in the year with the circuit there.”

Balancing races with recovery is tough when promoters come calling with the lure of another appearance fee and a potential prize. Lessons have been learned, he says, from the mistakes of this year when wear and tear led to injuries that hampered his progression up the rankings. “I probably travelled around a bit too much. I dotted here and there without a clear plan,” he said.

There’s not a doubt, though, that today’s trip will be worth the heartache. “I know I’m going to train and set myself up for hopefully a successful season,” he shrugs. A gift that will keep on giving when the decorations have long since been packed up for another year.”