Published: Mar 01, 2013 3:38 PM EST
Updated: Mar 01, 2013 6:03 PM EST

COLLIER COUNTY, Fla.- "I always say, keep breathing," said Francis Smith.

Francis Smith's secret to living a long life must be working because he's 105 years young!

"I've always been reasonably athletic and active," said Smith.

He's become quite a celebrity at the Planet Fitness in Collier County where he's been working out for the past 4 years. Today, the gym hosted a birthday party in his honor.

"Not many people know someone who's a hundred, much less a 105, and who has all their faculties," said Priscilla Smith.

Smith and his wife, Priscilla, are not just celebrating a birthday today, but also their 30th wedding anniversary.

"We enjoy our life together," said Mrs. Smith.

Including working out together at the gym.

"I work out only because he comes to the gym. I would not come on my own, but I usually feel better for it," she said.

And how does he feel afterwards?

"Tired. I work out and then I sleep," he said.

He works out three days a week.

"I'm putting a little bulk on."

Twice at the gym and once with a trainer.

"I'm not gaining in strength, I just try to keep up, keep the muscles the way they are instead of deteriorating," he said.

Mrs. Smith believes it's the secret to her husband's longevity.

"So as long as he keeps coming to the gym, there's no medicine that's going to keep him alive, but that will," she said.