Hartmuth’s background carries a disquieting contrast. Sheholds a PhD in climate science from ETH Zürichand specialized in atmospheric and climate science. While preparing for the 2023 Trail Running World Championships she trained and defended her doctoral thesis at the same time.Her institution — ETH Zürich — is the same alma mater of Albert Einstein.

Her sporting career also began unusually. Hartmuth started out as a sport-climbing enthusiast and “incidentally” became a top trail runner. To this day she refuses to hire a coach; all her training plans are self-prescribed, “because she likes to train independently.”

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She once said in an interview: “I give meaning to every training session I do for myself. But I always follow how I feel.” For someone who must balance high-intensity research with extreme sport, that autonomy is not just a training choice but a way of life.

In 2022 she first drew attention at UTMB’s TDS (147 km), finishing third; in 2023 she won silver in the long-distance category at the World Trail Running Championships and was runner-up in the UTMB main race the same year.

In 2024 Hartmuth prepared seriously for the Tor des Géants for the first time, winning in 79:10:40 to become the first woman in history to complete the race in under 80 hours; she finished seventh overall and improved the previous women’s course record by more than an hour.

Hartmuth’s strength, viewed against everything she has been through, seems all the more remarkable.

In spring 2024 she was hit by a car while cycling, suffering a serious knee injury that required surgery. The accident disrupted her entire season’s preparation; she admitted she “couldn’t do the ideal training.”Less well known is her long struggle with depression.

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In the 2025 personal documentary Katharina, she candidly discusses her struggles with mental health. Directed by Ethan Newberry (The Ginger Runner), the film had its world premiere during UTMB 2025 and was described by reviewers as "an intimate character study about mental health, perseverance, and the fine line between strength and vulnerability."

She once said a line that has been widely quoted: "Just as you would see a doctor if you broke your arm, if you're depressed, seek help."

In 2025,she experienced the extreme condition of "temporary blindness during the race" at the Hardrock 100.Her Hardrock that year was troubled almost from the first kilometre — pre-race stomach upset left her sleepless the night before, and in the opening ten kilometres she felt her "legs had absolutely no power." She recovered somewhat mid-race, but in the second half struggled to eat, ran out of energy, and then lost her sight.

She ultimately finished with the help of her pacer in 32 hours 39 minutes 48 seconds, claiming third place for the second consecutive year. That same year she also placed third woman at UTMB.

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In July 2026 she reset the women's record for the Bob Graham Round in England's Lake District with a time of 14 hours 11 minutes 58 seconds — the classic challenge of 106 km, roughly 8,200 m of ascent, circling 42 peaks. She shaved 22 minutes off the previous mark set by Beth Pascall in 2020.

Even more remarkable: she flew to England from the San Juan Mountains in the U.S. just two days before the attempt, carrying jet lag and the fatigue of altitude training, with the weather window about to close. With almost no time to prepare she decided to go. She described it as "the coolest day since I started running."

On the 2026 Giants' Journey, Hartmus showed unusually bold ambition from the start. At the La Thuile checkpoint (19.1 km) on day one she was third overall, only 1 minute 37 seconds behind men's second Bai Xingzhi. By Valgrisenche (48.5 km) she remained the leading woman and was seventh overall, just 27 minutes back from the leader Zhao Jiaju.

As the race moved into the second night and third day the drama intensified. Zhao Jiaju chose to rest at Gressoney (203.3 km), temporarily ceding the lead, and Swiss runner Schindler moved ahead. Hartmus kept close to the two male leaders, arriving at Valtournenche (236.7 km) at 7:05 — only 8 minutes after Schindler had left the station.

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On-site photographers captured the back-and-forth between Hartmus and Schindler. At the Magià hut (255.4 km), as Schindler was preparing to depart, Hartmus had just come into the station and the two exchanged a brief conversation.

"Next is that long descent to Oyace (274.4 km) — it really is long," Schindler said. "Long, very long," Hartmus replied. "But we'll get there," Schindler encouraged. Hartmus sat down, ordered a plate of tomato-sauce pasta and drank German apple juice, and calmly said, "Last night went well, but there's another night ahead of me."

That exchange was described as "Wonder Woman joins the fray."At that point the gap among the top three was under half an hour. Hartmus barely rested, occasionally dozing with her head on a table, and her elapsed time was already about three hours faster than the time she set in 2024.

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By the time they reached 307.5 km, her gap to men's second Schindler had at one point narrowed to just five minutes. With 30 km remaining, whether the leading woman could catch the men's second became the race's most breath-taking subplot. Her goal had shifted from rewriting the women's record and aiming for the podium to contesting the overall title.

Giants' Journey was founded in 2010 and is the only race in the world that combines an ultra-distance of 330 km with 24,000 m of cumulative ascent. In the event’s 16-year history, no female athlete had ever reached the overall podium.

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What Hartmus achieved in 2026 was more than contesting a women's title. Her close, late-race duel with two top male competitors meant she became the first woman in the race’s history to stand on the overall podium. Zhao Jiaju's coach even used Hartmus's charge to motivate his athlete; Schindler dared not linger long at aid stations on the course, “because Hartmus was right on his heels.”

In the end, Zhao Jiaju broke the record and won in 65 hours 55 minutes 22 seconds (65:55:22), becoming the first Chinese champion in Giants' Journey history. Hartmus finished third overall in 67 hours 10 minutes 09 seconds (67:10:09), again claiming the women's title and shattering her own women's course record by more than 12 hours.

A climate scientist raced alongside the world's strongest male ultrarunners for nearly three days on the brutal Alpine course. She had no coach and no team designing a training plan for her — she worked out for herself how to run faster than almost all the men on this “hellish” course.

Studying the future of the planet's climate in scientific research, and battling her body's and mind's limits in the mountains —Hartmus's story is far more than the outcome of a single race.She proved that in a sport defined as humanity's ultimate endurance test, gender is no longer a ceiling but merely a footnote that needs rewriting.