‘Women Can Do This’: She Started Racing Postpartum in Her 30s. Now She’s an Ultrarunning Champion
Most days, Careth Arnold wakes up at 5 a.m. Before the sun rises, the first thing the professional ultrarunner does is a body check—examining how her muscles feel after processing mileage from the day prior.
Once she determines the status of her body, the mom of two selects her workouts for the day—sometimes with inspiration from ChatGPT. Usually it’s a road session in the morning and a trail run in the afternoon, when she has a nanny and can enjoy the mountain views around her home in Paonia, Colorado. Most mornings, she has until 7:15 a.m. to finish before her daughters, Cypress, 6, and Shiloh, 2, wake up.
Since starting out as a competitive runner in late 2020, Arnold has experienced a meteoric rise in the sport—while becoming a mother at the same time. Last year, she won the 95-mile TDS Ultra, becoming the first American to claim the title since the race’s inception in 2009. On April 24, the 36-year-old finished second at the Canyons Endurance Runs 100K, after recovering from a long bout of illness that sidelined her for most of the winter.
Though she’s quickly emerged as one of the greatest ultrarunners in the world, Arnold is still very much figuring out what works best for her. Right now, that means being self-coached and taking an intuitive approach to running.
In those quiet morning hours on the roads, Arnold sets the tone for her day. Like most moms, it’s a dance of managing schedules, mealtimes, and childcare. For Arnold, that means striking a balance between 100-mile weeks in training that challenges and fulfills her, while also respecting the demands of her life.
“My big takeaway from this season is just trying to find my own rhythm—trying to find who I am as an athlete versus [making] comparisons,” Arnold says. “Like, who am I as an athlete in my individual self as a mother?”
An Artist’s Path to Running
Unlike most professional runners, Arnold never competed in track and cross country at the youth level. She played soccer and rugby in high school. For most of her formative years, Arnold mainly focused on her work as an artist.
She went to Ringling College of Art and Design in Sarasota, Florida, where she earned a BFA in fine arts. In between classes, she’d go out for some easy miles a few times a week. It wasn’t until her early 30s that she decided to take running more seriously.
In 2020, Arnold was working as a horticulturist when the pandemic hit. With her husband, Derek Brinks’s job being remote, they decided to travel west with a trailer in tow from their home in Florida. Along the way, they stopped to see family in Austin, Texas, where she ramped up her mileage on the city’s rolling hills and scenic greenbelt trail. It didn’t take long for Arnold to see the appeal of racing—and her potential in the sport.
In the fall of 2020, Arnold was eight months postpartum with the couple’s oldest daughter, Cypress, when she ran her first marathon. Curious to see how fast she could run, Arnold completed the virtual New York City Marathon starting from her house. She anticipated finishing in four hours or less, trying to stay on schedule with breastfeeding. Carrying a few dates, almonds, and a water bottle for midrun fuel, she ended up running 3:23.
“Since then, I’ve always wanted to see how I can improve upon that time because speed is a challenge for me, and I think it’s a challenge for everybody. But I didn’t run collegiately, I didn’t run in high school, so it’s not like I have a foundation in speed,” Arnold says. “I’ve just been teaching myself and trying to train my muscles.”
In February 2021, Arnold completed her first trail race, the Swamp 30K in Palm Coast, Florida, and won the competition outright in 2:49:41. At the time, Arnold was still breastfeeding and navigating postpartum incontinence, but the experience was transformative nonetheless.
“I loved the way that I got to push my body. I remember peeing myself for half of [the race] too, but at the same time, still loving it,” she says. “It was just a massive feeling of being so satisfied.”
An Unexpected Talent
For the next couple of years, Arnold designed her own training plans using online research and signed up for more competitive trail races. Being postpartum during the start of her running journey, Arnold also wanted to embrace being more in tune with her body and give herself flexibility. She topped the podium on many occasions, including back-to-back wins at the JW Corbett 50K.
One of her biggest breakthroughs came at the 2023 Bandera 100K when she finished third in the women’s race to course record-holder Courtney Dauwalter and runner-up Nicole Bitter—both legendary trail runners. The sports marketing team at Altra also took notice of Arnold’s rise.
Though there was much to celebrate at the time, Arnold also faced a devastating low. When she was in discussions with the Altra team manager, her mom died suddenly. Shortly after signing a professional contract with the brand, Arnold found out she was pregnant with her youngest daughter, Shiloh.
“It was a lot to wrestle with. There’s not much I remember, but I do remember running a lot…I needed it to emotionally process,” Arnold says.
Looking at her results that year, you wouldn’t guess that Arnold was pregnant. In February 2023, she finished sixth in the 60K at Black Canyon Ultras. That April, she placed second at the American River 50 Miler, during her second trimester.
While she was running through grief, Arnold was also curious to test her strength as a pregnant runner—exploring what her body was capable of, within healthy limits. If something felt off, she’d back down in the workout, which happened more frequently toward the end of the pregnancy. She also turned to cross-training and reduced her mileage.
“[Running while pregnant] had its challenges, but at the same time, I was like, women can do this. Our bodies are strong,” Arnold says.
When she was seven months postpartum, Arnold finished fourth at the 2024 Canyons 100K, where she earned a roll-down entry into the Western States 100—one of the most prestigious trail races in the world.
Two months later, Arnold toed the line of her first 100-miler in Olympic Valley, California, with bags of breast milk stored in coolers and a plan to use her breast pump at aid stations along the course. Because the weather conditions were warm that year, Arnold became dehydrated and her milk supply didn’t replenish fast enough, which meant she couldn’t pump during the race. After battling intense fatigue for much of the last 30 miles heading into Auburn, Arnold finished 14th in 18:53:39.
“I had to really fight through some mental hurdles that 100-miler,” Arnold says. “As soon as I finished, I was so depleted, I was vomiting. And then getting back to my hotel, Shiloh was just sitting right there waiting for me, and we nursed for an hour.”
Prioritizing Self-Care in Running
Two years ago, Arnold started working with a coach for the first time—training under Nicole Monette. Her most significant victory to date came last fall at the Sur les Traces des Ducs de Savoie (TDS) trail race, where she finished in an astonishing 22 hours, 58 minutes, and 52 seconds on the course that includes 29,527 feet of elevation gain across the Alps.
With the momentum from TDS, Arnold expected to start this season by testing her speed at the Austin Marathon in February. But the flu spread through her entire family a week prior to the race and took an expected toll on her body. After going out around 6:30-mile pace for most of the first half, Arnold felt depleted early on and dropped out just after mile 13.
In the weeks following the disappointment in Austin, and still dealing with prolonged bouts of illness with bronchitis, Arnold hit a low point and realized she needed to take a step back from traditional, structured training. For the time being, she is self-coached.
“I needed to be able to problem solve things as I go, especially when I was dealing with sickness. I also needed to give myself space to intuitively run based on the day, my kids, my health,” she says. “I just felt like, if I can free my stress of having to stick to a plan for a bit, maybe I can find some joy and actually play a little bit more with my training.”
In the most recent training cycle, Arnold created her own buildup rooted in flexibility and self-care. She wanted to explore what her body could do each day as opposed to what was written out on a training plan—while also taking into account the demands of caring for her youngest daughter, Shiloh, at home. For two weeks, that translated to logging 100 miles of running and 50 miles of cycling—her highest mileage ever. In other periods, she needed to take time off to recover from everyday stressors.
“As a mom, sometimes it’s really hard to do a workout when you’ve been up all night with your kid who is vomiting," she says. “Maybe you don’t want to do a workout that day. Maybe you want to do a trail run, something more therapeutic, or maybe you don’t even want to run because you're so tired.”
The first big test of her new training approach took place on April 4 at the Running Up For Air six-hour race in Moab, Utah. Arnold tore through the looped course, climbing up steep, rocky terrain and flying down slickrock to cover nearly 28 miles in the allotted time. She won the race outright. Three weeks later, she finished runner-up in the 100K at Canyons in 9:56:36, her fastest time ever on the course in Auburn, California.
In just her sixth year running, Arnold has already learned a valuable lesson some athletes never fully grasp. “Every one of our bodies, minds, and spirits is so unique and so different that you have to fall into your own rhythm,” she says.
Now that she’s discovered hers, there’s no telling how far she’ll go.
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For the past decade, Taylor has reported on sports, health, and wellness for leading fitness publications including Runner’s World, SELF, Bicycling, and Outside. She’s also a podcast host and film producer focused on amplifying the stories of women and other underrepresented communities in endurance sports. When she’s not writing, you can usually find her running—or eating breakfast tacos with her family in Austin, Texas.
