When he visited his grandpa’s house in Illinois this summer, Caleb Prewitt noticed the most recent photo on the wall only had one of his Guinness World Records.
“We need to send him the picture of me with two,” Caleb told his mother, Karen Prewitt.
That new photograph, though, will be outdated by the end of summer, as long as things go according to plan for the 19-year-old from Florida.
Caleb is competing July 18 in the Sombrero Sizzler, a 12-hour race in Jacksonville, Florida.
If he runs at least 50K, Caleb will become the youngest person with Down syndrome to finish an ultramarathon.
“There’s only two other people with Down syndrome that we know of that have done ultras,” Karen said. “One did a 50K and the other one lives in Poland and he did 43 miles.”
‘A believer in running and exercise’
Caleb, like the 5.4 million others in the world who have Down syndrome, was born with a 50% chance of having a heart condition.
“Caleb was included in there,” his mother said. “He was born with two heart defects.”
One resolved itself with age, but the other, a ventricular septal defect, could linger the rest of his life.
“He sees a cardiologist every couple of years,” Karen said. “The cardiologist is very happy that he’s out and active and running. He doesn’t have any restrictions on exercise or movement or anything.”
Learning that her son was free to compete in athletics was welcomed news for Karen, who has a degree in physical education.
“I’ve always been a believer in running and exercise,” she said. “I just think it’s beneficial to him, and anybody really with Down syndrome if they consult their doctor first, to be active.”
He lift weights, swims, rides a bicycle and runs.
“We work out with my muscles,” Caleb said.
Nearly 5,700 babies born in the United States each year have Down syndrome, according to the Centers for Disease Control, which means that Down syndrome affects one of every 640 children.
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First two Guinness World Records
Caleb’s first competition came as a 3-year-old at the Special Olympics of Florida. The events were easy back then, with a focus on balance, stability and coordination.
“A lot of people with Down syndrome, their hips are wider, so they kind of waddle,” Karen said. “They teach them all the basics of sport, like how to throw a ball correctly, how to walk a balance beam, which helps with balance and stability, and the form of running.”
As an 8-year-old, Caleb competed in his first race: swimming.
“He loved being in the water,” Karen said. “And then COVID came.”
During the pandemic, the boy’s mother decided it was time to introduce him to the world of running.
“We set our goal at running a 5K on Thanksgiving, and that was 2020,” Karen said. “We started in gosh, probably August, and he did it. That was his very first race was the 5K at Thanksgiving.”
Caleb kept training and, after a few months, was starting to log some serious miles. Pretty soon, a family friend pointed out that a half marathon was within reach.
On Feb. 4, 2024, Caleb ran the Donna Half Marathon in Jacksonville Beach, Florida. He was 16 years and 326 days old when he finished the race, which made him the youngest person with Down syndrome ever to run 13.1 miles.
“He finished in three hours and 21 minutes,” Karen said. “If you know anything about Down syndrome, 321 is a very special number because Down syndrome is three copies of the 21st chromosome. We thought that was pretty special.”
Caleb’s second Guinness World Record came on Aug. 20, 2023, when he finished an Olympic triathlon in Starke, Florida, in four hours and 21 minutes, which is the fastest time ever by someone with Down syndrome.
After both races, Caleb stole the show by dancing at the finish line, a ritual he loves as much as the races themselves.
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‘A very surreal experience’
The boy’s fame continued into adulthood. By June of 2025, he decided to register for the Chicago Marathon through the National Down Syndrome Society.
“He and 17 other runners got picked to kind of be on posters and billboards and kind of highlight their story,” Karen said. “That was super cool.”
Caleb and his mother trained all summer, mostly early in the mornings to avoid Florida’s hot summer afternoons.
On Oct. 12, 2025, Caleb and 50,000 other runners tackled the Chicago Marathon. He enjoyed the crowd, but things got a little difficult around mile 23.
“My leg,” he said. “It cramped.”
After some electrolytes, bananas and lemonade, he was ready to start running again.
“He got to high-five people all along the course,” Karen said. “They were cheering his name. It was just a very surreal experience, I would have to say. And being his mom and running, I’m going to cry now, but running it alongside of him was very special.”
He finished the marathon in seven hours and 50 minutes, which could have been another world record until Caleb bested his own time on April 26, 2026, by finishing the London Marathon in seven hours and 28 minutes.
“It’s a very long process to apply,” Karen said. “You have to send in all the data and you have to have witness statements.”
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‘The ability of people with Down syndrome’
This year, Caleb and his mother have been training for his attempt at an ultramarathon. After running 26.2 miles twice, they think 31 miles is within reach.
“I think it’s doable,” Karen said. “He’s done two marathons, about seven hours for both, so I think 31 miles in 12 hours is pretty doable.”
The Sombrero Sizzler is 12-hour race on a 1.25-mile loop. The terrain is a flat mixture of pavement and grass.
“We would love to do 55K, but if he gets to 50K and he’s done, so be it,” Karen said. “He will still be the youngest, so he can still claim that title. But if he gets to 55K, that would be super cool.”
Caleb has a lot of friends who are coming to watch his race, clapping and cheering after he finishes each loop. He also plans to run with music to keep his energy levels high.
Karen and her son have been training together all summer, incorporating an ice bandana and several new fueling options into their routine.
She plans to run with him the entire way, a practice she learned keeps him focused during events longer than a few miles.
“He gets really into his music, to the point where he will stop running and start dancing,” Karen said. “It’s like, ‘Come on, buddy, we’re going to keep running.’ We try to keep a 14- or 15-minute pace.”
If all goes well, Caleb could have four Guinness World Records by the end of the year.
But no matter what the official time ends up being, Caleb enjoys running, and said he likes the way the activity makes him feel, both mentally and physically.
“One of the whole goals is really to show the ability of people with Down syndrome,” Karen said. “We get messages from parents of little ones all the time. People with Down syndrome are going to college and starting their own business. We have a friend who is an artist and he makes a great living at it. So, you know, they can do all kinds of things, they just need support and opportunity.”
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