Tom Bogan exiting the Boulder reservoir as he finished the swimming portion of the Ironman Boulder last year. 

(Courtesy Tom Bogan)

Five years ago, Boulder dentist Tom Bogan didn't know how to swim. But the 57-year-old learns quickly. This October, he will head to the Ironman World Championship in Kailua-Kona, Hawaii, which includes a 2.4-mile open-water swim as well as a 112-mile bike competition, and a 26.2-mile foot race. 

Bogan, who will compete on Sunday for a second year in Boulder's Ironman, found out in December that as an early entrant to the Boulder race he received one of 10 randomly selected wildcard spots for the Hawaii competition. The Kailua-Kona Ironman is considered the most prestigious race of its kind in the world. 

Bogan says he never had a consistent exercise regime until he was in his 50s but once he started, he was hooked.

These days, when Bogan isn't peering into the mouths of his clients at his dental office in North Boulder, he's training. He says he works out for about 14 hours a week. 

Tom Bogan speaks with Colorado Matters host Andrea Dukakis.