The elevation profiles — graphs of elevation changes — for the Breckenridge 100 mountain bike race look like readings off an electrocardiograph that has either gone haywire or is hooked up to somebody having a heart attack.

The latter is not hard to imagine, given that most of the 14,000 feet of elevation gain on the 100-mile race course in Colorado takes place at more than 10,000 feet above sea level.

But the winner of Sunday’s race, Amanda Carey, is a specialist in this kind of cardiac madness.

The Victor, Idaho, resident is a two-time champion in the National Ultra Endurance Race Series, made up of a dozen 100-mile mountain bike races across the U.S. every summer.

By winning the Breckenridge 100 on Sunday, Carey identified herself as a clear favorite for a third NUE championship and as one of the “baddest” mountain bike racers in the country.

The Breckenridge event does not have as much vertical gain as Pierre’s Hole, a 100-miler that takes place at Grand Targhee Resort and climbs almost 16,500 feet, but its high elevation clearly makes it one of the most difficult races in the NUE series.

Carey skipped Mountain Bike Cross-Country Nationals two weeks ago to prepare for the Breckenridge 100. Instead, she competed in the Outerlocal Summer Games in Jackson, because the long, steep climbs on Snow King were better training for Breckenridge than the course at nationals.

Carey admits none of the races are easy.

“Every single time I finish one of these things,” she said, “I am grateful I survived it.

“I operate in full-on, 110 percent race mode,” she said. “People ask me what I think about, and I tell them I think about racing. I think about how I can go faster and if I am doing everything I can to go as fast as I can.”

Going all out and completely dedicating herself to what she is doing is a recurring theme in Carey’s life.

Growing up in Ipswich, Mass., Carey said, she devoted herself first to horseback riding and later to basketball and softball.

“I have a pretty obsessive personality,” she said. “Anything I do, I get really into.”

Carey didn’t discover her threshold for pain until she started working as a porter for the Appalachian Mountain Club. Carrying fully loaded packs to and from the huts in the steep Appalachian Mountains taught her to dig deep and fight through the hurt.

She moved to Jackson in 2000 to focus on snowboarding, her newest obsession at the time.

When the snow melted, she started mountain biking.

“I had no idea what I was doing when I first got into mountain biking,” she said. “I crashed a lot and was constantly beating myself up.”

She learned to bike the same way she learned to snowboard: by following people who were faster than her.

“I really like the sensation of seeing my hard work pay off,” she said. “Working toward improvement and then seeing improvement is very satisfying, very rewarding.”

In 2008, she turned pro.

Sponsored by Felt bicycles and Kenda tires, she competed in cyclocross, cross-country and stage races. But after her first ultra-endurance competition, she knew, “This is it, this is where it is at.”

She likes the longer races because there is “more bang for the buck.” Most races, she said, last only around an hour and a half. NUE races can go on for anywhere from eight to 14 hours. Considering Carey really starts feeling good around six hours into a race, she made the right choice.

Also, she said, the feeling of accomplishment at the end of a 100-miler is extremely rewarding.

Carey said she also likes the sense of community at NUE races. When she was doing cross-country mountain bike races, she felt the professionals were very separated from the amateurs. At NUE events, she feels there is an “awesome community of people,” she said.

“Clearly I am not in this for any sort of financial reward,” she said. “I have always stayed true to what makes me want to race.”

She enjoys the hard work, the accomplishment and the learning.

“I learn something about myself every race,” Carey said. “At Breckenridge I learned a lot about racing at altitude and that discipline in my race strategy can work.

“I tend to start 100s very fast,” she said. “I like to see who can keep up and then settle into an endurance pace.”

Given the altitude of Sunday’s race, Carey planned to start out more conservatively, which took an enormous amount of discipline. She kept Jari Kirkland — the 2011 and ’10 Breckenridge 100 winner — a couple of switchbacks behind for most of the race, and the strategy paid off.

Carey won the women’s race with a time of 10 hours, 9 minutes and 1 second. There are seven more races in the series. Somebody will have to  take first place four times to challenge her in a tiebreaker.

NUE races are less common in Europe, which makes her one of the best long-distance mountain bike racers in the world. But she said she doesn’t get treated like a celebrity, which is just fine with her.

“I don’t consider myself special,” Carey said. “I consider myself a hard worker.”