Most people preparing for their first 100km ultramarathon focus on the training. The long runs, the back-to-back weekends, the nutrition experiments. What they think about less is what the day itself is actually going to feel like — hour by hour, section by section.
That gap between expectation and reality is where most first ultras go wrong.
I have been racing ultras since 2012 — Badwater 135 in Death Valley, Ultra Gobi 400km, Spartathlon from Athens to Sparta, MOAB 240. I have coached marathon runners through their first 100km on the coastal roads of Okinawa's Yanbaru forest. And in all of that experience, the single most useful thing I can give a first-timer is a map of what the day is going to feel like before they live it.
Here is that map.
The first 30 to 35km of a 100km ultra will feel easier than they should. You are fresh, adrenaline is present, the scenery is new, and your body is telling you everything is fine.
This feeling is not a lie exactly — but it is incomplete information. Your body does not yet know what is coming.
The most common mistake in any ultra is going out too fast in the first third. You pay for it in the final third, with interest.
In my second Ultra Milano-Sanremo — 285km from Milan to the Italian Riviera — I controlled the opening pace while runners of every description passed me. I finished third overall. In my first attempt at the same race, I did not control it. I walked the final 100km in considerable pain.
For your first 100km: the opening 30km should feel almost too easy. Comfortable conversation pace. If you feel like you are going too slowly, you are probably going the right speed.
The rule: If people are passing you in the first 30km and you feel the urge to go with them, don't. You are not racing them. You are managing a day.
Between roughly 35 and 65km, most runners find a rhythm. Things feel manageable, the body has settled, and the finish feels distant but imaginable.
This is also where the first significant rough patch tends to arrive.
Somewhere around kilometers 55 to 70, most runners hit a wall of some kind. Legs that suddenly feel heavy. A wave of fatigue that seems to come from nowhere. A mood drop that makes the remaining distance feel impossible.
This is normal. It is not a sign that something has gone wrong. It is the ultra revealing itself.
The correct response is not to push through aggressively and not to stop. It is to reduce to a walk, eat something, drink something, and wait.
In my experience, the overwhelming majority of these patches resolve within 20 to 40 minutes if you address the physical basics. What usually feels like a crisis of the spirit is actually low blood sugar or mild dehydration wearing philosophical clothing.
The rule: When it gets hard, don't decide anything. Walk to the next support stop, eat, drink, and give yourself 20 minutes before making any judgment about how the day is going.
After 65km, the run changes character. Everyone is tired. The difference between runners now is not fitness — it is how well they have managed themselves to this point.
The runner who started conservatively, ate consistently, and walked when walking was smart has something left. The runner who burned too bright early is running on stubbornness alone.
The final 35km can be genuinely joyful if you have managed well. I have had late sections in ultras that were among the best running experiences of my life — tired but moving, the body in that strange state where pain and pleasure become hard to distinguish, the finish close enough to feel real.
That experience is available to you. It requires patience in the early hours.
If your 100km includes a night section — and most do, at this distance — you need to know what to expect.
Your headlamp creates a small circle of light and removes the peripheral world. Without visual variety, your mind starts producing its own content. Thoughts become strange. Time distorts. Objects can look like things they are not.
I have had full conversations with fence posts I was convinced were checkpoint staff. This is called sleep-deprivation hallucination and it is entirely normal in long events. It is a signal that your body wants sleep, not a sign that something is medically wrong.
The night also gets cold. Fatigue lowers your tolerance for temperature considerably. A layer that seems unnecessary at the start of the evening becomes essential at 2am. Pack it. Carry it. Use it.
The rule: The night is a different psychological environment. Slow down slightly, stay fuelled, and expect your mind to get strange. It passes.
In fourteen years of ultrarunning, across four continents, I have never had a race where the legs were the deciding factor. The deciding factor was always the conversation happening in my head — particularly in the dark, at 3am, when the body is exhausted and the mind starts asking very uncomfortable questions about life choices.
The good news: that conversation is trainable. It improves with experience. And it improves fastest when you understand, before the race, that the low points are temporary.
Almost nothing is as permanent as it feels at 3am.
That is the most useful thing I know about ultrarunning.
On the Yanbaru 100k route — the coastal roads of northern Okinawa from Ogimi Village to Cape Hedo and back — the shape of the day maps closely to what I've described above. The first section runs along the coast with views across the East China Sea. The middle section climbs into the Yanbaru forest. The final section, often run in darkness, follows the road home along the western coast.
It is hilly — genuinely hilly, not "a few gentle slopes" — with approximately 1,800 meters of cumulative ascent. It is also one of the most beautiful running routes I have found in fourteen years on four continents.
If you are a marathon runner thinking about attempting your first 100km, the Yanbaru 100k guided ultra runs November through March. Details at yanbaru100k.okinawaultra.run.
Michal Činčiala is a Czech ultra runner and coach based on Hamahiga Island, Okinawa during the camp season. He has raced Badwater 135, Ultra Gobi 400km (10th overall), Ultra Milano-Sanremo 285km (3rd overall), Spartathlon, MOAB 240, and the Authentic Phidippides Run 500km. He coaches marathon runners through their first 100km ultra on the roads of northern Okinawa.
Running your first 100km in Okinawa — guided, coached, semi-supported on the Yanbaru coast.
Learn about the Yanbaru 100k →