Whether It’s Running the Cocodona 250 or Hiking the Trans Bhutan Trail, This Penn Vet Clinician Says: “Think Big”

The Cocodona 250 has been called The Race that Breaks You.
An ultramarathon of 250 grueling miles that begins in Arizona’s Sonoran Desert, it dares some of the best runners in the world to endure nearly 39,000 feet of elevation gain through unforgiving terrain, desert heat, and freezing mountain heights. Some participants train for years and still don’t finish the course. People bleed. They hallucinate. This year, one runner died.

Anyone might toe the starting line with trepidation.

Not so one decidedly unconventional contestant: Rose Nolen-Walston.

“I wasn’t nervous. I was super-excited!” said Nolen-Walston, a Penn Vet associate professor of large animal internal medicine. “You start at 5 AM, and it’s the most exciting, wonderful feeling. It’s absolutely jet black. Here we go!”

And in 121 hours this past May, the veterinarian was one of those determined runners who did finish this year’s Cocodona, bolstered by stops for an hour of sleep here and there, snacks from Walmart, the two friends who served as her support crew, and the camaraderie of fabulous fellow runners she met along the route.

Back home, her family in England, her wife of 32 years Alice, daughter Ali, and her many Penn Vet students here were cheering her on. They knew better than to worry. It was the kind of experience Nolen-Walston has embraced much of her life.

“I think people don’t think big enough,” she said, laughing a bit. “Think big, man! Think big and do hard things.”

Actually, the Cocodona was Nolen-Walston’s second ultramarathon. The first was the C&O Canal 100 in April 2025. She signed up for that one on a whim. Didn’t train at all.

“By the end of the race, I was like the favorite village idiot at all the aid stations because I was really happy and positive. I was having a good time, and they’d be like, ‘Here comes our non-runner!’”

To qualify for a commemorative race buckle, a runner has to finish the 100-mile course in 30 hours. Nolen-Walston made it in 29 hours and 47 minutes.

“I came back to work the next day, and I couldn’t walk. Then I got kicked by an alpaca and ended up in hospital for rhabdomyolysis, which is when all your muscles break down. I was absolutely crippled for about three weeks,” Nolen-Walston recalled. “It turns out you should not run a 100-mile race without training. It’s a bad idea.”

She did train for the Cocodona. Sort of. About four months instead of other competitors’ two to three years. She didn’t have that much time, so she approached it with the “growth mentality” she encourages in her students. Rather than saying you’re bad at something, think in terms of just needing more practice.

Getting ready for the big race – by way of Planet Fitness and Bhutan

So, she ran every morning, hit the Stairmaster at her local Planet Fitness in the evenings, and hiked through the Central Pennsylvania mountains every weekend.

And then there was Bhutan. In late 2025, Nolen-Walston hiked 250 miles along the Trans Bhutan Trail. Attempting the full trail is rare, and many who make even part of the journey do it glamping style – with SUVs, fancy tents, lots of equipment. Nolen-Walston decided to make her 18-day journey with just a backpack and a guide, camping in Bhutanese forests, sleeping on floors in humble homes, and partaking in the generosity of Himalayan Mountain people.

Singay Dradul, Trans Bhutan Trail Exploration Officer Representative, called Nolen-Walston’s achievement “extraordinary” as well as “unique”. Not only did she trek the entire trail self-supported, carrying all her essential gear and supplies, but, he added, she did it setting the fastest known time on the route.

“This record-setting journey is an inspiration to fellow adventurers and a testament to what can be achieved through passion, preparation, and perseverance,” Dradul said. 

For her Bhutan adventure, Nolen-Walston hired an online coach to help her get fit. He had her do some running. That came in handy when she had to avoid a venomous King Cobra encountered on the trail and scramble away from an angry yak displeased at getting his photo taken. The whole experience helped make her stronger for the Cocodona – in body, but in spirit, too.

In one video she posted to Facebook, she talks about sharing a Thanksgiving dinner – “one of the most beautiful Thanksgivings I’ve had” – of potatoes, chilis, rice, and greens with a local family. The mother carried her baby on her back while she cooked. Nolen-Walston helped churn butter. The light was soft. They had no language in common, but it didn’t matter.

“We are just enjoying our Thanksgiving,” she said on the recording, “just (thinking) what a remarkable world this really is”

It’s a video she keeps, along with the good luck posting her students sent her before the Cocodona. Both are dear to her in their own way.

Nolen-Walston would probably be one of the first people to tell you there’s no one path to living a big life. She’s never taken the predictable road in hers.

“I actually was a very, very unathletic child, and I was such a bad runner that in school they stopped making me run in gym class. I was allowed to just hand out the orange slices,” she said, recalling her English childhood. “So, I’ve always had this identity as a non-runner.”

She didn’t plan to become a veterinarian, either, or, for that matter, a teacher.

“I wanted to be an Olympic dressage rider,” she said. There was a problem: “I was hampered by a complete lack of talent.”

That didn’t stop her. At 15, she dropped out of high school to chase her dream.

“I travelled around the world from age 15 to probably 22, working at these dressage farms and being terrible. I was just not a very talented dressage rider. I was adrift.”

Her family was not pleased about her decision to quit school, but “they were happy I was alive. I was a teenager who struggled. So, they were like, ‘Well, at least she’s out there doing something.’”

And Nolen-Walston was out there, working in exchange for lessons on farms in Germany, the Netherlands, the United States, her Olympic aspirations no closer to reach.

But at one point in her journey, she found herself doing equine therapy for residents of a home for severely emotionally disabled children in Georgia. A lot about it just clicked.

Her boss, who had been a childhood friend of her mother, told her she should be a horse veterinarian.

“I hadn’t been in school for years at that point, so I did a little bit of undergraduate (coursework) at (the former) State College of West Georgia. I did really well. I had a 4.0 GPA.”

She kept taking classes and became a chemistry major. The faculty at the small school took her under their wing. Before very long, she had enough credits to get into the University of Georgia College of Veterinary Medicine.

“I only did a year and a half of undergraduate, but I got all of my requirements for UGA vet school,” Nolen-Walston said. “So, I haven’t graduated undergrad, either. The only thing I’ve ever graduated from my entire life is vet school. No high school diploma, no undergrad. Just vet school.”

Charting her own path, her own way

It was just the beginning of an unconventionally accomplished life.

“I have a history of doing hard things, not necessarily taking the conventional path,” she acknowledged. “I didn’t take the conventional path to vet school. I didn’t take the conventional path to running the Cocodona 250, and I am sure I’m the only person in that race for whom that was the first race they ever trained for in their life.”

The path less taken has worked quite well for Nolen-Walston. Having joined Penn Vet’s faculty in 2006, she is a beloved educator. In 2014, she won a University of Pennsylvania Lindback Award for Distinguished Teaching, and in 2017, she received the Zoetis Distinguished Teacher Award.

One of the years she won a Lecture Teaching Award, a student described her teaching style this way: “Thrilling, riveting, mind-blowing, action-packed and on-the-edge-of-your-seat comedy, Dr. Nolen-Walston’s lectures are like the most exciting movie release of the year, and you just happen to have a ticket.”

As a veterinarian, she is well-respected in her field. Five years ago, after 20 years in internal medicine, she wanted to try something different.

“I had a year of sabbatical accrued. My department chair Katrin Hinrichs was nice enough to allow me to do a second residency. So I went to Tufts, and I spent a year just going back to being a student again. I did a residency in clinical pathology.”

Since then, Nolen-Walston, who was already boarded in internal medicine, has become boarded in clinical pathology as well “just for fun.”

In terms of other life adventures, Nolen-Walston is also a proud mom. Her daughter Ali shares her love of horses and riding.

“When she was a kid, she was a very successful pony jumper.” Nolen-Walston said. “She did pony racing and pony jumping.”

She has videos and photos of a determined-looking little Ali racing ponies in New York City’s Central Park and competing at Devon.

“I go off and do things that most people would find too scary or too intimidating, and the apple does not fall far from the tree with her,” Nolen-Walston said. “When she was 13 years old, she flew to Slovenia and spent the summer with strangers learning to ride jumping horses. She lived in a little hut by herself, did her own shopping. She’s a tough cookie.”

A smart one, too. A medical student at Sheffield University in England, her daughter is currently doing a research year in Philadelphia. In time, she would like to do a residency in cardiology at Penn.

Her mother, meanwhile, is still processing the unexpectedly “magical” experience of the Cocodona 250.

“There’s something really astoundingly meaningful, kind of at a gut level, of challenging yourself to do something that almost feels impossible and then being successful at it. As I was doing it, I was surrounded by other people doing the same thing,” Nolen-Walston said. “I came out of it feeling changed in ways I wasn’t expecting.”

“I was expecting it to be hard, but I wasn’t expecting it to be so transformative. It will probably go down for me as one of the top five most meaningful things I’ve ever done.”

Which raises the question: Is she planning on another Cocodona next year? True to form, there’s another challenge she wants to try.

It’s called the Last Annual Heart of the South Road Race.

“You drive to a parking lot in Georgia, and a strange man puts you in a bus with all the other competitors, and he drives you 350 miles away. You don’t know where to,” Nolen-Walston said. “Then they drop you off, and they give you a map. You have to find your way back, but you have no crew and no support, so you’re just buying food from gas stations along the way, sleeping in the dirt on the side of the road, and you have 10 days to make it back.

She was laughing: “It’s going to be crazy.”