Former Marine Sgt. Michael Mendoza understands first-hand how the power of staying active can play into benefiting mental health for the men and women returning home from overseas deployments.

The 38-year-old was a sniper in Iraq when a grenade blew up in front of him, extensively injuring both of his lungs, collapsing his diaphragm and damaging his stomach and small intestines.

It took nearly a year for him to recover physically after his 2006 injury -- and has taken a good part of the past decade to overcome many of the mental and emotional effects that followed.

“When I was injured, I kept to myself a lot, withdrew from my friends and family,” Mendoza told Fox News on Tuesday. “There are still family I don’t speak to and I needed to go through that.”

A track athlete in high school, Mendoza eventually picked up running and in the process of meeting other athletes and veterans it all “began to click.”

“It all started clicking. I started to become outdoorsy. I started feeling really good,” he said. “Recovery through sport and recreation – that’s my goal, my mission.”

After running his first full Ironman last year, Mendoza wanted another challenge: to break the Guinness World Record for most long-distance triathlons completed in a single year. He also wanted to break the record for most Ironman Ironman 70.3 – or Half Ironman – triathlons in a year.

One record stands at 23, the other at 18. He hopes to run 26 – unless he decides to add another one in there.

“In December I was sitting on the couch and I told my wife I wanted to break the record … she said ‘You’re crazy,’” Mendoza recalled. “[I said] that if I put my mind to it I could do it.”

Mendoza’s first Ironman 70.3 was March 19 in Arizona. Since then, he has run about four a month.

This past weekend he ran No. 18 in Maine and will tackle No. 19 at the Ironman 70.3 World Championship in Chattanooga, Tenn., on Sept. 10 as an Ironman Ambassador.

“I don’t have a break,” he said. “It’s almost like an addiction -- a good addiction.”

He added: “I never give up. I push myself every race.”

The Ironman 70.3 consists of a 1.2-mile swim, a 56-mile bike ride and a half-marathon (13.2 miles). In the 70.3 Ironman rankings, Mendoza sits in 11th place overall worldwide in his age group, and 6th in the United States.

The Chicago-native said he is running for two reasons: to capture the world record and to raise money for the Semper Fi Fund, which he said helped him and his family tremendously after he was injured.

“They flew my wife and son to my bedside, put them up in the Fisher House. That really helped me, emotionally and mentally. Had they not been there, I could have gone down a different path. So Semper Fi is very close to my heart.”

Semper Fi is an organization that helps injured and recovering service members.

Mendoza has raised nearly $20,000 since starting the journey. The goal is to reach $25,000 by the time he runs his final race in Mexico during Veterans Day weekend.

Mendoza, whose Silver Star was upgraded this year to the Navy Cross – the second-highest military decoration awarded for valor in combat – said that while he has been away from home pretty much every weekend since the spring, the journey has strengthened his relationships to family and friends.

“I have such a great support system,” he said. “My wife knows it’s only temporary … my son and daughter, they push me to race harder every week.”

His main motivation, however, are the men and women who return from overseas – many injured both physically and mentally. Many of whom are close friends.

“My buddy lost his eyesight, my other buddy lost both his legs,” he said. “They have their challenges and [it’s why] I don’t want to give up.”