Felicity Aston walking across Antarctica
Associated Press
Perhaps no one exemplifies this power of community more than Scott Jurek. Arguably the greatest ultra runner of all time, Jurek has won just about every major race of distances greater than 50 miles. He also has had a support crew routinely douse him in ice during a 135-mile race through Death Valley, Calif., and had friends accompany him on training runs that lasted for days.

In most sports, the closest an amateur can get to his idol is wearing a jersey, but the person who finishes last in an ultra often finds Jurek, the winner, cheering for him at the finish line. Races may be about competition­ on the course, but in the tight-knit communities of extreme athletes, completing a task is done, in part, through others out there giving more than they thought they had.

“I love that I can go to a race and volunteer,” Jurek says. “Engaging people and watching them cross the finish line allows me to relive what I go through.”

Part of what drew Steph Davis to rock climbing 20 years ago was the community. Davis was not particularly athletic and tried climbing while in college. She fell in love immediately and, a week into law school, she traded a steady career path for a life in the mountains.

“Through my 20s, I was anxious about material stuff, but I was also living in my car,” says Davis, a professional climber, BASE jumper and wing-suit flyer. “I think the idea of security is an illusion. A lot of people who have gone down the more traditional career paths have had their ups and downs too.”

In sports like climbing, the term dirtbag is treated with reverence. The most loyal members of these communities turn sport into a profession that usually pays almost nothing. Many of them have college degrees. They choose a life of sleeping in tents and bathing in frigid streams because every life involves trade-offs, and the freedom to pursue their passions is worth more than the perceived comforts that others pursue.

Motivation plays an outsized role in our abilities to achieve goals, and researchers have found that although extreme athletes are among the most motivated people, their motivations differ from those of others. While working hard may lead to higher pay, which will lead to a bigger house in a better school district and on and on, professional rock climbers or surfers seem more aware of and able to overcome the never-ending loop of this line of thought.

They push themselves harder so that next time they can take it a step further. The reward is in achieving a goal as well as in being able to see something new; to go deeper into the woods or higher into the sky the next time.

“It’s not just about the challenge,” says Dieffenbach. “It’s about being able to continually see and experience new things.”

What drives these athletes more than any other motivation is the goal of surviving while continually pushing. They want to survive so they can keep trying, and that is where intelligence and discipline come in.

After a year of climbing, Davis began free-soloing — climbing without ropes — some extremely challenging peaks. On her first attempt, 1,500 feet above the base of Longs Peak in Colorado, the fear of falling struck her.

She climbed the route four more times that summer: Her fear of falling had transformed into a fascination.

“You can’t climb without a rope if you’re going to get scared,” she says. “I wanted to learn more about falling, so I started skydiving.”

Skydiving led to wing-suit flying (leaping from a high altitude with a suit that allows one to slow the speed at which he or she falls, translating that into forward momentum), which led to BASE jumping. These sports are considered some of the most dangerous in the world, but Davis does not have a death wish. She is a published author who has a happy life with her husband in the beautiful town of Moab, Utah. So why increase the level of complexity?

“These people are very smart and analytical,” Dieffenbach says. “They enjoy planning routes and developing a strategy for the next challenge.”

Extreme sports offer intelligent people a way to hone and use their skills without having to be tied down to the strictures that so often exploit those talents, she explains. The comparison to musicians and artists is frequent in the research for this reason. The artist analogy is also frequent in the athletes’ appreciation for every moment, but there is one way in which it fails: A mistaken brushstroke won’t kill you.

It seems almost a contradiction that these athletes love life so much yet put it at risk, but the awareness of the precious ephemerality of every movement gives them the power to avoid worrying about what might happen so they can appreciate what is happening right now.

“Part of loving life is doing everything you can to appreciate it while you’re here,” says Davis, reciting a mantra familiar in her community. “I never have that feeling of, ‘I wish I could have gone down that road,’ because I have gone down it. That’s what life is all about.”

Ethan Rouen is a Ph.D. student at Columbia Business School and a contributing writer at Fortune.com. He writes about (and sometimes partakes in) crazy sports and sane sports for American Way.