One night, on his trek up the tallest peak on Earth in a place called the death zone — where the atmosphere is cold enough to cause frostbite and the amount of oxygen is insufficient to sustain human life — Jeffrey Glasbrenner found himself suffocating.
"I was gasping for breath. My heart and respiration had slowed. It was a rough night," he recalled. "I needed to catch up on my breathing and didn't sleep the rest of the night."
Anyone who climbs Mount Everest knows the risks, said Glasbrenner, a 1998 University of Wisconsin-Whitewater alumnus.
The dangers are deadly. In May, at the same time Glasbrenner's team was on the famed mountain, seven people on other expeditions died of various causes, from exposure to frigid temperatures, altitude sickness, or snow blindness.
Going up and coming back alive depends on extensive mental and physical preparation. But that's just the start, Glassbrener said.
"You also need to make sure you travel with experienced climbers and smart guides who view safety as the number one priority."
He chose to climb with Madison Mountaineering, a mountain guide service based in Seattle, Washington. Members of the expedition included 15 Sherpas, seven climbers and five guides.
They arrived in Nepal on April 3 and embarked on a nine-day hike to base camp, where they completed three practice climbs to acclimate their bodies to the harsh conditions. During the course of the official climb, Glasbrenner's team battled ferocious winds, dodged falling ice, and pushed through a whiteout blizzard.
On May 18 — a sunny, calm day — they reached the summit. Twenty-nine thousand, thirty five-feet.
"Most days I feel like I am on top of the world, and on that day I literally was there," Glasbrenner said. "You can't see it in the photos, but I was all smiles under that oxygen mask. There was huge sense of accomplishment, to look back and see how far I'd come."
Scaling Mount Everest is an incredible feat for any human. For Glasbrenner, it was historic. He is the first American amputee to reach the summit.
Originally from Boscobel, Wisconsin, Glasbrenner suffered a near-fatal farming accident when he was 8 years old that left him a below-the-knee amputee.
He describes it as his "greatest opportunity" — a moment that would define his life.
His journey led him to UW-Whitewater, a campus with a mission to help students with disabilities thrive, where he studied marketing and human resource management.
"It was amazing. It was the first time I was really exposed to someone else with a disability. It turned out there was a whole group of us that was different."
A natural athlete, Glasbrenner discovered wheelchair basketball and found mentors and coaches who pushed him to succeed.
"My experience at UW-Whitewater taught me to surround myself with the right people who didn't look at my leg and see weakness. It opened my eyes to possibilities and inspired me to set and reach goals."
Glasbrenner won a collegiate national championship with the Warhawks. He later played for the Denver Rolling Nuggets, winning a national championship in 2004 after completing what is considered the greatest individual performance in wheelchair basketball playoff history — a record-shattering 63 points, 26 rebounds and a 76 shooting percentage.
He played for the U.S. Paralympic team in Sydney in 2000, Athens in 2004, and Beijing in 2008.
He is an author, motivational speaker, and a married father of two children who has completed 25 Ironman distance triathlons.
His next challenge is to climb the "seven summits" — the highest mountain on each of the seven continents.
Two years ago, in preparation for his Everest climb, Glasbrenner scaled Aconcagua in Argentina, the highest mountain in the western hemisphere. Then there was Everest in May 2016. Two down, five to go.
"I hope my story inspires people to set goals and accomplish them, whether it's graduating from college or running a 5K," he said. "If a person with one leg can climb Mount Everest, what else is possible?"