At 7 a.m. Monday, while most of us were dreading the thought of another encroaching Polar Vortex, 142 people were venturing out to spend hours — and in many cases days — competing in the coldest of cold places.

The Arrowhead 135 race started at that time in International Falls, Minn. As the name suggests, participants then cover 135 miles on a snowmobile trail — but they have no motorized vehicles to carry them. Instead, they have the option of cycling, skiing or running.

Who are these people?

"They are a hardy group. They are some of the most elite athletes around," race director Jackie Krueger said. "Reading their résumés and applications was fascinating."

Feel free to add crazy, stubborn and any other descriptor of your choice. It was minus-24 degrees at the start line, with windchills approaching minus-50. The fastest cyclists, pedaling through snow on "fat" tires, were expected to finish shortly before midnight Monday. The fastest runners could take 48 hours to complete the course, and they might not see temperatures above zero the entire time.

To finish, though, is to earn a badge of honor — particularly this year, when temperatures are even cold for that region. The average high in International Falls on Jan. 27 is 16 degrees, according to weather.com.

Not finishing? Well, there is no shame in that even if it sometimes brings disappointment. By 6 p.m., 24 competitors had dropped out. Todd McFadden, last year's winner on bicycle, was pulled from the course at the first checkpoint Monday because of frostbite. All racers were being checked carefully at each stop.

"Some people came in wild-eyed, like 'What have I gotten myself into?'" said race volunteer Russell Loucks, who was at the start line and the first checkpoint before heading late Monday afternoon to the finish line at Fortune Bay Casino near Tower, Minn. "But some were dialed in and ready to go, in and out within 10 minutes."

Much of it depended on how prepared racers were for the elements. When asked what is appropriate to wear for so many hours in the bitter cold, Krueger jokingly said, "Everything you have."

By now, though, competitors generally know what to expect. This is the 10th year of the race, and there have been some that approached this year's event in terms of extreme cold. In 2007, for example, bitter temperatures meant only 10 of 46 racers made it to the finish line. Krueger guessed that 30 percent of this year's field would make it.

And many of them wouldn't have it any other way.

"I always laugh and say 'the colder the better,'" Krueger said. "It helps the reputation of the race."