When Nick Nisbet says he once hit rock bottom, he means it.

"I had a heroin overdose. I stopped breathing for too long, and I died. My heartbeat stopped and brain waves stopped," he said. "They had to jump-start me with the paddles."

The 2006 episode finally persuaded Nisbet to kick his deadly drug habit. But getting clean -- and staying clean -- was a daunting proposition.

"I'd tried to get sober many times," the 34-year-old said. "I tried the methadone clinic, I tried just cold turkey. But ... you need to fill the void with something."

He tried 12-step meetings, but they depressed him. So when his girlfriend told him about Phoenix Multisport, a sober support community that offers free athletic activities, he agreed to check it out.

"I reluctantly went, thinking it was just going to be a big waste of time," he said. "Turns out it was the best move I ever made in my life."

Phoenix, named after the mythical bird that rises from its ashes, helped Nisbet rediscover his love of biking. It also connected him with other recovering addicts who wanted to be active.

"They just make sure that you're staying sober and having fun doing it," he said. "It's the best support crew I could imagine having."

More than 4,700 people have participated in Phoenix, which Scott Strode started in 2007. Most join the group because they've struggled with drug or alcohol addiction.

"Life should be better once you get sober," said Strode, 38. "(We want to) help people build a new life, a new self-image and have fun without getting high."

Strode developed his approach through hard-won personal experience. He started drinking when he was just 10 years old. By 15, he was using cocaine.

His addictions intensified after college. One night, after a bender, he woke up on the bathroom floor.

"Suddenly it dawned on me that if I didn't change things, I was going to overdose and that was going to be how my mother would find me," he said.

He decided to give it all up for good. But that meant abandoning his entire social network, as everyone he knew was involved in drinking and drugs.

"Overnight, your friends are gone, you're alone," he remembers. "It was a depressing first three months of recovery."

Eventually Strode started working out at a boxing gym, and he later got involved with triathlons and climbing. These new activities kept him busy, and they also made him feel good.

"You start to believe you can succeed in whatever you do, whether that's your sobriety or ... crossing the finish line," he said.

But for Strode, the most important factor was that many of the people he met through these activities were sober. With these friendships, he built a new support system.

"It was surrounding myself with a group of people that would rather get up at 7 in the morning to climb a mountain than to stay up until 7 in the morning drinking and using," he said. "With influences like that, I just moved further away from the darkness of my addiction."

In 2005, during a climbing trip, Strode realized that New Year's Eve had passed and he hadn't given so much as a thought to drugs or alcohol. He decided he wanted to share what he'd learned with others. A year later, Phoenix Multisport began offering programs in Boulder, Colorado.