One of ultrarunning’s most beloved figures is fighting for his life after a shocking medical emergency cut short his race at one of the sport’s most prestigious events.
Jeff Browning, the 55-year-old American ultrarunner known affectionately as “Bronco Billy,” suffered a heart attack during the TDS race at UTMB in Chamonix, France — just 16 kilometers from the finish line.
He was airlifted to hospital and, according to early reports, is currently in a coma.
Here’s everything we know so far — and why the ultrarunning world is holding its breath.
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What Happened on the Course
Browning was approximately 129 kilometers into the grueling 145-km TDS race when he required emergency medical attention.
That’s nearly 80 miles of mountain terrain already behind him — with only 10 more miles to go.
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Race and emergency medical teams responded immediately, treating him on the course before a helicopter airlifted him to a nearby hospital, where he remains under medical care.
His family wasted no time in reaching out to the thousands of fans following his journey, releasing an official statement through his Instagram account.
During the TDS race at UTMB in Chamonix, Jeff suffered a heart attack. He received immediate medical treatment from the race and emergency medical teams before being airlifted to the hospital, where he remains under medical care.
A Fall, Blurry Vision, and a Frightening Chain of Events
Details are still emerging, but what’s being pieced together paints a deeply concerning picture.
Earlier in the race, Browning reportedly took a fall and broke his glasses. He later posted an Instagram story — now taken down — mentioning blurry vision, though he appeared upbeat at the time.
It was later in the race that things took a serious turn. Browning received defibrillation at an aid station before being transported to hospital by helicopter.
Vespa Power Products, one of Browning’s sponsors, shared a message from UltraAspire CEO Bryce Thatcher on Facebook that revealed the severity of his condition — and raised a troubling possibility about what may have triggered it.
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Jeff is in a coma after having what is believed to be a heart attack around mile 80 of the TDS Race at the UTMB World Series in Chamonix. It is highly probable Jeff’s fall could have caused a brain bleed, creating pressure on the brain and triggering a heart attack. But details are few, and at this point this is speculation and a best guess.
Specialists are now investigating whether an intracranial hemorrhage or epidural hematoma from the earlier fall may have set off the cardiac event.
The Facebook post has since been taken down or had its visibility restricted.
Who Is Jeff “Bronco Billy” Browning?
For anyone unfamiliar with the ultrarunning world, Browning isn’t just a participant — he’s a legend.
Over nearly two decades of competition, he has completed close to 200 ultramarathons and claimed victories in more than 40 of them. That level of consistency is almost unheard of in a sport that destroys most athletes’ bodies long before they reach their 50s.
At 47, he won the iconic Hardrock 100 — one of the most punishing hundred-mile mountain races in the world — finishing in an impressive 26 hours, 20 minutes, and 22 seconds.
Then, rather than slowing down, he kept pushing. At 52, he crossed the finish line of the Cocodona 250 in second place. That’s a 250-mile race. Done at 52 years old.
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Beyond his own racing, Browning has given back to the sport in every way imaginable — through coaching, pacing, course marking, and mentoring the next generation of ultrarunners.
A Community in Shock
News of Browning’s collapse has sent shockwaves through the ultrarunning community, where he is widely regarded as one of the sport’s most genuine and inspiring figures.
The TDS — Sur les Traces des Ducs de Savoie — is one of the marquee races within the UTMB World Series, drawing elite athletes from around the globe to the Alps each year. Finishing it is already a monumental feat. Browning had covered 129 of its 145 kilometers before his body gave out.
At 55, he was still out there competing against some of the best endurance athletes on the planet. That fact alone speaks volumes.
What Happens Next
Right now, information is limited and the situation remains fluid. Browning’s family has not released further details beyond the initial statement, and the medical team’s findings are still being established.
What is certain is that the ultrarunning world — and sports fans everywhere — are rallying behind him.
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- Full-body training with one weight using swings, squats, and presses
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If Bronco Billy’s career has proven anything, it’s that this man has an extraordinary capacity to endure. The road ahead will be his hardest race yet — but an entire community is cheering him on every step of the way.
