There's a thin man in running gear pounding the pavement on SW 344th street in Florida City Thursday , talking to us as we drive alongside.

"I'm doing this to raise awareness for childhood obesity," said Alexis Garcia.

Garcia is talking the talk, and way more than just walking the walk.

"I believe the kids are spending too much time nowadays behind the computers and games and there has to be a balance," Garcia says, never slowing down to speak.

He knows what he's talking about. As a physical education teacher at the Miami Lakes K-8 Center, he sees tons of out-of-shape kids.

"Absolutely, that's one of the main reasons why we are doing this, we want to make sure that the kids exercise more, are more active," Garcia said.

So Garcia is running, virtually non-stop, from Crandon Park on Key Biscayne to Key West, 190 miles to make a point. He's guided by his wife and friends, who are following along in a van decorated with a poster signed by all the kids in the after-school running club that he founded. It's called "Just Run", which provides exercise and community service programs for 75 students, two days a week.

"That means a lot to me," Garcia said. "When I feel tired, all I have to remember is they're backing me up, that's a big push."

190 miles sounds like a long way to run, and it is, but compared to Alexis' journey to the United States, this is a walk in the park.

"I left Cuba in 1992, in a kayak," Garcia explains, never missing a beat as he runs. "I was in the Straits of Florida for 55 hours until Brothers to the Rescue found me, lost and desperate, but I made it, and when I touched land for the first time, it was, as a matter of fact, in Key West."

Garcia is one of those intensely driven, goal-oriented people. But he says no one should say they can't exercise, they don't have time, it's too hard.

"Those are simple excuses," the phys-ed teacher bristles. "I used to be a heavy smoker for 21 years, I decided to quit, and I started walking, just walking, one step at a time."

That led to marathons, and now a super-duper marathon to the Southernmost City.

"It's gonna be really tough, but I don't have any doubt that I'm gonna make it," Garcia says.

Neither do we.