"My daughter's got a masters in nutrition and my son is heavily involved in the fitness industry himself.
"They were blunt and honest [and] made it clear to me what health-related issues were likely to crop up in the next five to 10 years."
Dean's story is a familiar one - he played a bit of squash when he was younger, but once his kids were born and his career kicked off he found it difficult to find the time to exercise.
"I was working in a sedentary job, sitting in an office, drinking a few too many beers, and just getting bigger and bigger," he says.
It seems a long way to go from that state of affairs to 10 Ironmans on the trot but, as Dean explains, it was a gradual change.
"I recognised there was going to be some [health] issues and I wasn't very fit at all.
"So I decided I would start cycling. I got on the bike and just started doing a few kilometres - you know, 10km was a long way.
"And then in 2002 I thought I would do the Taupo [Cycle Challenge] bike ride.
"I went around in a pretty slow time, and I just got interested from there," he says.
When he was in Taupo one year he decided to take a look at the Ironman race as a casual spectator. It set something off inside his head.
"I saw all these people that were really grinding it out.
"A lot weren't perfect athletic specimens, and so I thought 'I can do this'."
From that point, Dean entered a couple of half-Ironmans before taking on the full-length race.
"I did the first one in 2005 just to see if I could get to the end inside the cut-off time," he says.
But the arduous course wasn't the only problem Dean faced on that first outing.
"About a week out, I slipped over and fractured my wrist.
"So I actually completed [the race] with a cast on right up to my elbow, which made it pretty difficult swimming and riding on the bike."
Dean finished inside the cut-off time, and has been addicted to the race ever since.
He says the benefits to his physical health have been significant.
Before he started competing in Ironman, his Christmas present measured his resting heart rate in the mid 70s. Now it's down to the high-40s.
"It's a good indicator of my fitness," he says."I just feel better inside myself. I'm physically in better shape than I was in my mid-20s.
"I think it's helped me stave off having to start taking medications for blokes my age. I don't take anything.
"I don't have any blood pressure problems. I think that it's helped me immeasurably."
The great race
What:
Kellogg's Nutri-Grain Ironman New Zealand.
When:
Saturday, March 7.
Who:
Open entry, but athletes must be 18 or older on race day.
For more information, visit:
www.ironman.com