The 100th by UTMB (Andorra) – How to face the Pyrenean altitude
I’ll never forget the first time I toed the start line of the 100th Andorra UTMB 2025. At that moment, I thought I was ready. My legs were trained, my gear was dialed in, and I had scouted the route online at least a dozen times. But nothing—absolutely nothing—can prepare you for the way the Pyrenees test every inch of your body and mind. Over 105 km, the terrain pushes you into steep ascents, exposed ridgelines, and hauntingly beautiful valleys that steal your breath, both figuratively and literally.
In this article, I want to share what I learned from this incredible adventure: key strategies for acclimatization, how to manage altitude effectively, and technical highlights that make this course one of the most challenging yet rewarding races in the UTMB World Series.
Acclimatization: the most underrated part of your training
If you’re training for the 100th Andorra UTMB 2025, do not underestimate the importance of altitude acclimatization. The race reaches over 2,800 meters (more than 9,000 feet), and even though you may not feel the effects right away, the altitude creeps up on you over time—especially during the second half of the course.
For me, the key was arriving at least a full week in advance. I based myself in Ordino and gradually built up my exposure, doing short hikes and easy jogs at progressively higher altitudes. By day four, I started to feel normal again above 2,000 meters. This gave me a crucial edge when others began to struggle with headaches or nausea halfway through the race.
Tip: Sleep low, train high. If you’re staying in the valley, make sure to include daily runs or hikes above 2,000 meters. It trains your lungs to work harder while still allowing proper recovery.
Know your effort zones at altitude
Even if you’re a strong runner at sea level, your body reacts differently at altitude. During the 100th Andorra UTMB 2025, I made the mistake of pushing too hard on the first major climb—nearly 1,300 meters of gain right out of the gate. By the time I reached the first summit, I was lightheaded and my legs felt fried.
After that, I switched to using heart rate and perceived exertion as my guide. While power hiking, I kept my breathing controlled and focused on efficiency. On the descents, I used them to recover, not to hammer.
Nutrition and hydration: adjust for the Pyrenees
One major lesson from the 100th Andorra UTMB 2025 was that I needed more fluids than I expected. The combination of altitude, sun exposure, and long stretches without aid made it very easy to get dehydrated. I used a combination of water, electrolytes, and salty snacks to maintain balance.
Altitude also affects appetite. Around kilometer 65, I found myself unable to stomach anything sweet. I had packed too many gels and not enough solid food. That mistake cost me time. Fortunately, one of the aid stations had soup and potatoes—lifesavers in that moment.
Technical terrain: more than just altitude
What sets the 100th Andorra UTMB 2025 apart isn’t just the elevation—it’s how technical the terrain is. Nearly half the course feels more like a mountain scramble than a trail run. Expect scree, sharp rock ridges, wet descents through pine forest, and narrow ridgelines with exposure.
Poles were essential for me. I also used trail shoes with aggressive lugs, and I’m glad I did. Several sections would’ve been dangerous in slick or worn soles. And don’t forget headlamp quality—a good beam makes all the difference on loose, uneven terrain during the night sections.
Mental preparation: darkness, solitude, and awe
There’s a moment in the 100th Andorra UTMB 2025—somewhere around the 80-kilometer mark—where you’re deep in the mountains, far from any civilization. The stars above look close enough to touch, and the silence is almost overwhelming. It was both beautiful and eerie. That’s when I realized this wasn’t just a physical race—it was a mental one.
The solitude can mess with your head. I practiced mental mantras, repeated checklists out loud (“Eat. Drink. Move.”), and kept a photo of my family in my pack to stay grounded.
Visualization helped me immensely in training. I pictured tough spots and how I’d handle them. That preparation paid off when the real low moments came.
Race-day gear choices: what worked and what didn’t
For the 100th Andorra UTMB 2025, the mandatory gear list is strict—and for good reason. Weather can swing from summer heat to snowstorms in hours. I carried:
- Lightweight waterproof jacket and pants (used both during a late-night downpour)
- Merino base layer (a savior at dawn)
- Two headlamps with fresh batteries
- Poles (used them from start to finish)
- 2 liters of hydration capacity
- Solid food and backup emergency nutrition
What I didn’t expect was how cold it got above 2,500 meters, even in late June. I ended up wearing everything I had packed. Next time, I’d also bring a buff or face cover for wind protection.
Don’t skimp on cold weather gear. In the Pyrenees, it’s not optional—it’s survival.
Final push: the climb that breaks your soul
The last major climb before returning to Ordino is infamous. On paper, it doesn’t look much worse than earlier segments. But after 90 km in your legs, it’s a beast. The trail gets steep, rocky, and almost vertical in places. Every switchback feels endless.
But here’s the thing: it’s also the moment you realize how far you’ve come. I remember seeing the sun rise again from the final ridge, painting the granite walls orange. That was the moment I knew I’d finish.
Crossing the finish line of the 100th Andorra UTMB 2025, I didn’t feel like a stronger runner. I felt like a different person.
Final thoughts: should you run the 100th Andorra UTMB 2025?
Absolutely—if you’re ready to be humbled and inspired in equal measure. This race offers everything a mountain ultra should: challenge, scenery, solitude, and the kind of experience that stays with you forever.
Train smart. Arrive early. Respect the mountains. And don’t forget to look up—because in Andorra, the sky really does start at your feet.
