If you're an endurance athlete looking for the ultimate test of mind, body and spirit, you'd be hard-pressed to find anything more challenging than the Patagonian Expedition Race. Averaging more than 370 miles, the 10-day race is not a marathon over backcountry roads and cleared trails, but a full-on sprint through never-before-touched wilderness, foaming, freezing waters, ever-shifting glaciers, and a variety of other settings unheard of in competitive sport.

The 2016 edition, the first since 2013, will feature 20 teams of four people taking on course stages that include trekking, sea kayaking, navigating and mountain biking. Just to make things even harder, the course information is made available only 24 hours before the race begins. After that, you and your teammates basically enter another world — both physically and mentally. In 2013, only 30 percent of the teams completed the race.

“We saw every type of terrain you could imagine," endurance athlete and 2010 competitor Stephen Regenold recalled on GearJunkie. "It looked like New Zealand, the Alps, Colorado, there were jungly sections and the Turba (peatbog) was crazy — it looked like the set from the movie 'Avatar.'"

More than just a competitive challenge, the Patagonian Expedition Race is also an environmental billboard, drawing awareness to the region's fragile and diverse flora and fauna, while also enforcing a "leave no trace" and "cup free" policy for all participants. "We must protect and preserve this remote and pristine region of Chilean Patagonia," race director Stjepan Pavicic said in a statement. "Our event brings this message to the world."

So what kind of physical and mental mindset is needed to tackle a challenge of this magnitude? For that answer, I was fortunate to speak earlier this summer with SheriAnne Nelson, a long-time fitness and nutrition coach, mother of three, and competitor in next February's Patagonian Expedition Race. Nelson is the captain of USA Adventure Addicts, which is vying to make history as the first all-American team to win the expedition.

SheriAnne Nelson'I love a good challenge. I think it really shows you who you are,' SheriAnne Nelson of USA Adventure Addicts told MNN. (Photo: SheriAnne Nelson)

"I've always had this burning desire to push the limit and to just be what's possible," Nelson said. "And I came across this article in Outside Magazine and it was the 13 Toughest Races in the World and the Patagonian Expedition Race was in there. And I had seen that race a couple of years back when eco-challenges were popular, and I thought, 'well, this looks kinda cool.'"

At the time, Nelson says she was searching for a new challenge after a stretch of competing in five Ironman triathlons over three years. When the Patagonia opportunity came along, she was drawn to not only its grueling course, but also what appeared to be the Herculean feat of even crossing the finish line. But first, she needed to sit down with her family to see if dedicating a year of her life to making it happen was even possible.

"It's a two week commitment, let alone a full year for the prep work," she said. "I needed to have everyone on board with what I was doing due to the demands that it was going to take to prepare for a race of this nature. And my whole family was like, 'Oh awesome, let's go. We're behind you!'"

USA Adventure AddictsUSA Adventure Addicts during a recent team training weeking in the Grand Canyon. (Left to right: SheriAnne Nelson, Jeff Kline, Lee Kyler and Aaron Spurlock) (Photo: USA Adventure Addicts)

Over the next several months, and with the help of her personal coach Jeff Kline, Nelson set out to fill the remaining three slots on the team. The athletes who eventually came on board — Bryan Hay, Lee Kyler and Aaron Spurlock — round out what's an extremely diverse and motivated team spread out across the U.S.

"We're everyday Americans," Nelson said. "We have a pharmacist that's also a student, we have a computer programmer, a school teacher and myself. So we all have our lives. We're not professional athletes. We don't have people funding this. So it's not like we can at the drop of a hat all show up at a race to gain experience and gel with one another."

In an effort to prep for next February, in addition to their personal races (Ironman competitions, 100-mile marathons) throughout the year, the team has been meeting whenever possible to bond, train and study the skills necessary to succeed in Patagonia. So far, they've conducted weekend training in the Grand Canyon and in the wilds of the Adirondacks of New York.

"We are doing the best we can to coordinate training weekends where Jeff drops us in the middle of nowhere and says, 'Here's you at Point A. You need to get to Point B and you've got two days to get there.' We're doing the best we can at simulating the conditions of Patagonia, but the reality of the situation is that Patagonia is so harsh that it's next to impossible to kind of create that on the front end."

The team is also using this opportunity to give back –– partnering with the non-profit ZERO in an effort to raise awareness and money in the fight against prostate cancer.

"One in every seven men will be diagnosed with prostate cancer and most don't catch it until it's too late," Nelson said. "And it's actually a very devastating cancer for men. People need to talk about it more. I have become very passionate about sharing the awareness and encouraging men to go get checked and encouraging women to make sure that their men go get checked. I'm proud and very honored to be partnered with ZERO."

Thanks to a strong social media presence on both Facebook and Twitter, you can continue to follow Nelson and the rest of the team as they further prepare themselves for what's sure to be the adventure of a lifetime. The next steps involve not only the physical, but also the mental endurance needed to compete and win what's described as the "world's last wild race."

"It's important that as a team we're gelled, so that we can get along in stressful situations," Nelson added. "Because if we can keep the humor and the lightheartedness, than we can get through anything. But it's a matter of you've got to suck it up and make it work. Over the next six months, that's a huge part of getting ready."

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Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

U.S. aims to win 2016 Patagonian Expedition Race
Spanning 10 days and hundreds of miles, the challenging course takes competitors through the most remote and untouched regions of Chilean Patagonia.