"I packed it in my transition bags, and it was just my time," he said. "I wasn't a triathlete, I was a diabetic man eating lunch."

When Perry first told his doctor he was going to train for a triathlon, he got a response that eventually got him across the finish line.

"I called my doctor and I told my doctor, 'I want to try and do this Ironman,' and he said very passively, 'Yeah, good luck,'" Perry said. "And I just recall the way he said that. It lit a fire under me."

At first, Perry struggled to complete a lap of swimming (a triathlon is equivalent to about 87 laps in the pool), but after 362 days, he was able to finish.

Not only did Perry learn a lot about himself during that time, he learned a great deal about diabetes.

"Around for the entire month of August, I think I took very little insulin the entire month," he said. "I fine-tuned my body that great that I literally, I took very little insulin. I don't want to go as far as saying I cured my body, but I wrote everything down that I was eating. I eliminated all the things that clearly didn't work. I stuck with the things that did work."

For Nerothin, Grimm and Perry, their time training and fighting diabetes has inspired them to not only continue running, but reach out and help others.

Nerothin made it his mission to teach others everything he knows and to help them reach their goals, whether that be crossing a finish line or just getting a better grasp on their diabetes.

"It was such a wake-up call for me," he said. "I felt completed to go out and teach people because it was something that was just not being taught."

And Perry said that, for him, stopping will never be an option.

"I'm committed to it for the rest of my life," he said. "Every single year, I will do at least one Ironman triathlon. What I've learned is that this exercise makes that big of a difference. I believe if I stop exercising, I will lose the battle with diabetes. There's no doubt in my mind."