Adventurer Colin O’Brady felt like his hands were being crushed.

It was his 48th day trudging through Antarctica, attempting to become the first person ever to walk the 930 miles from one end of the continent to the other completely unassisted.

But battling through a particularly nasty storm, the 12-hour days spent gripping ski poles combined with wind chill temperatures as low as -112 degrees Fahrenheit left him barely able to close his hands.

Amidst his pain and confusion, as he set up his tent, he neglected to ground it to his sled. A wind gust transformed it into a sail, and O’Brady, 33, grabbed it in a panic, as its loss would have meant certain death from exposure.

“If I lost my grip, everything that kept me alive would be gone in seconds,” O’Brady writes in his bestselling memoir “The Impossible First: From Fire to Ice — Crossing Antarctica Alone,” (Scribner), out now.

Colin O’Brady trekking across Antarctica.
At times, Colin O’Brady battled windchill temperatures of -112 degrees Fahrenheit, making it hard for him to even close his hands and perform basic tasks.

“With no backup shelter and no hope of rescue, the end would come relatively soon,” he explains.

But as the tent “jerked over my head like a flag,” he was saved by a brief lull in the wind.

“I yanked the tent toward my body and wrestled it to the ground,” he writes. “After one of the most intense and fearful moments of my life, I had the tent back under control. I had my home back.”

O’Brady, an experienced triathlete from Portland, Ore., already held the world record for finishing The Explorers Grand Slam — climbing to the tallest peak on all seven continents, including Mount Everest, and reaching the North and South Poles — in just 139 days.

Colin O' Brady
Colin O’ Brady

While he couldn’t know exactly how long the journey would take — the weather was an all-encompassing variable — O’Brady initially planned to carry 70 days’ worth of fuel and food (eating 7,000 calories per day), which would have put his sled at over 400 pounds. He also brought a sleeping bag specially designed for Arctic temperatures and a portable stove.

But on the plane to Antarctica in late October 2018 — the beginning of the continent’s summer season — he found himself seated next to “the most intimidating man I’d ever met.” He turned out to be the explorer O’Brady would be competing against.

Captain Louis Rudd, 49, spent three decades in the British military and had participated in previous expeditions to the South Pole.

Rudd regaled O’Brady with stories of his 2011 trip to the South Pole alongside some of the world’s greatest adventurers.

Colin O’Brady trekking across Antarctica.
O’Brady at first planned to consume 7,000 calories a day, but dropped that to 6,000 in an effort to lighten his load — which led to severe weight loss.

“It was a brutal expedition,” Rudd said. “Severe storms. Henry [Worsley] and I each lost more than four stone. That’s something like sixty pounds to you Yanks.”

Worsley, a noted explorer, had died in 2016 attempting the same excursion they were now en route to. An Englishman named Ben Saunders also attempted the feat in 2017 but abandoned the effort before the end.

“Rudd was getting inside my head,” O’Brady writes, “and with every hour, my confidence was shrinking.”

After Rudd told O’Brady he had packed for only 5,500 calories per day — leaving his sled considerably lighter — O’Brady removed five days’ worth of food in a panic.

To make matters worse, the next morning Rudd informed him that instead of starting several hundred miles from where O’Brady was beginning his route, he’d begin his journey just one mile away — essentially taking the same path.

Suddenly, it was game on.

I couldn’t help but cry . . . the tears immediately froze to my face.

 – Colin O’Brady, on feeling self-pity at -13 degrees Fahrenheit

O’Brady officially began his excursion on Nov. 3, 2018, when a plane dropped him off at the designated spot in -13 degree weather.

By this point, he had decided to drop his food rations down to 60 days. But even after he took his first steps, he discovered that he could barely move the 375-pound sled, his tent and other supplies.

“Something was very wrong and I couldn’t help but cry,” he writes. “I quickly learned how Antarctica dealt with such pity; the tears immediately froze to my face.”

As if on cue, he then noticed a figure in the distance: Rudd, pulling his sled with no hesitation.

Feeling defeated, O’Brady called his wife/business partner, Jenna, from his satellite phone. Jenna took charge, telling O’Brady they’d recalibrate his journey. She told him to set up camp just a half mile away, then aim for six miles the following day.

Back at home, Jenna and O’Brady’s mother did the math on the weight of his sled and the calories he’d need for the trip. The next day, Jenna texted him, telling him to remove five days of food, which brought him down to a 55-day supply.

O’Brady lightened his load and continued on, traveling nine miles that day. His journey had now begun in earnest.

O'Brady's journey across Antarctica.
O’Brady’s journey across Antarctica.NY Post/Mike Guillen

While one could anticipate going slightly mad surrounded by nothing but whiteness for days, weeks, months on end, O’Brady was burdened by enough immediate and practical considerations — determining how long he could walk, when to set up camp, thinking about Rudd, etc. — that his mind was kept busy.

He did speak with Jenna daily, giving her updates and sending her pictures through a satellite modem that she would then post to his Instagram account. Otherwise, his odyssey became almost contemplative.

“The weirdest thing of all about [my] deep internal dialogue was that somehow it pulled me deeper inside myself to the zone where the reality of my race with Rudd could be stilled,” he writes.

On the morning of day six, O’Brady saw a ghostly image in the distance — a red tent. When Rudd leaned out and waved, a stunned O’Brady waved back and continued on.

An hour later, O’Brady saw Rudd pushing on about a hundred yards behind him, following his tracks.

“It was another grizzled veteran polar trick,” O’Brady writes. “I was functioning as his navigational beacon, which meant he could relax a bit and not use his compass so much.”

O’Brady slowed so Rudd could catch up. “Good morning mate,” Rudd said. “I’ve got a bit of a suggestion for you.”

O’Brady, believing Rudd was trying to undermine his confidence, put an end to it.

“We’ve both announced to the world that we’re trying to be the first,” O’Brady said. “Look, I hope we both make a safe crossing. But we’re doing this solo, so let this be the last time that we speak until this is over.”

Rudd gave O’Brady an inscrutable stare and continued on his way. The two men trudged along for the next eleven hours in the world’s slowest footrace before Rudd stopped and set up camp.

The encounter changed something in O’Brady.

“I needed to keep going in a way I hadn’t before,” he writes. “I vowed that I’d go as long as he did, and then an hour longer. If he went nine hours, I’d go ten. If he went ten, I’d go eleven.”

O’Brady walked 20 miles that day, his best distance yet.

During one particularly rough stretch a few weeks later, he decided to listen to music for the first time on the trip and played Paul Simon’s “Graceland,” a cherished album from his youth. He danced on the ice and it felt like he was hearing the song for the first time.

By the 35th day, O’Brady had traveled 495 miles. Calling Jenna while already close to sleep, he wanted nothing more than to shut his eyes when she gave him an errand.

“I know you’re tired,” she said. “But I need you to call this number.”

O’Brady tried to beg off the new assignment, but Jenna was insistent. So O’Brady called the number she gave him on his satellite phone, and a man answered.

Next thing he knew, he was talking to Paul Simon.

O'Brady was reunited with wife Jenna Besaw in South America after returning from his solo crossing of Antarctica.
O’Brady reunited with his then-girlfriend Jenna Besaw in South America after returning from his solo crossing of Antarctica.Tamara Merino

O’Brady, it turns out, had posted on Instagram about listening to “Graceland” in Antarctica, and somehow Jenna tracked the singer down.

Simon asked him about the Antarctic chill, what other music he listened to there (his only six albums also included the Grateful Dead’s “American Beauty” and Bob Marley’s “Legend”), and, unironically, the sound of Antarctic silence.

“It’s an old songwriter’s cliche, but it’s true — the spaces between the notes are the most important parts of any song,” Simon told him. “So what’s that like?”

“The silence can open a door,” O’Brady responded, “and then there’s a whole world beyond that, especially down here where the empty ice goes on forever.”

By day 41, O’Brady had 15 days’ worth of food left — and estimated he still had 25 days until he reached the finish line. While he carried no scale, it was clear he’d lost a frightening amount of weight.

“I’m looking down at my body and I don’t recognize it,” he told Jenna that night. “I’m experiencing rapid weight loss [and] my wristwatch is sliding around on my arm.”

He had been eating 7,000 calories a day, including oatmeal and protein powder, freeze-dried dinners and ramen that he’d heat up, and protein bars made specially for him by a Wisconsin nutritional supplement company that called them “Colin bars.” But while he was burning 10,000 calories a day, leaving him already deficient, he would now be reducing his daily intake to less than 6,000.

"The Impossible First"

His hunger combined with the threadbare surroundings and months of exertion began to cloud his thinking.

On his 46th day out, he began to wonder if Rudd, then 35 miles behind him, according to Jenna, who was following his journey via his GPS, might have been a figment of his imagination.

“The more I thought about it, the weirder it seemed. Rudd’s existence was almost too convenient,” he writes. “Maybe I’d needed a Rudd, and so I’d created him in my mind.”

By day 53, with the end almost in sight, he decided to finish the trek in one massive 40-hour push. He officially completed his journey on day 54, reaching the finish line two-and-a-half days ahead of Rudd.

Before he did, though, he stopped to take it all in one final time, to thank the universe for such a remarkable adventure and to give thanks to the competitor who inspired his victory.

“You’re out there somewhere, Lou, and I’d like to express my gratitude,” he said into the void. “You’ve pushed me, and made me better for it. I hope your passage is safe.”

After accomplishing his goal, he waited for Rudd to complete his own journey, in order to “make a statement of respect, to honor a worthy competitor.”

When Rudd finally arrived, “he looked horrible and radiant at the same time, like the soldier he was,” O’Brady writes.

On the second night, the two warriors met outside Rudd’s tent to swap stories of their journeys. “Despite the differences that separated us and always would,” O’Brady writes, “we now had a bond that would last forever. We both leaned in and shared a warm hug.”