If you want to polarise a room full of cyclists, just ask them whether FTP vs endurance base cycling matters more for ultra-distance events. I’ve had this argument at 3 a.m. during a 400 km brevet, fuelled by caffeine gels and the kind of clarity that only sleep deprivation can produce. Here’s what I’ve concluded after riding roughly 30,000 km a year, completing multiple Everestings, racing the UBF Pyrénées 500, and surviving my share of brutal Belgian winters: for ultra distance, the aerobic base is everything and chasing your FTP without building that foundation first is one of the most expensive training mistakes you can make. As Cycling Weekly’s endurance training guide notes, building genuine aerobic capacity takes months of patient, consistent work. There is no shortcut.
This article breaks down the real difference between these two training approaches, why the cycling community gets confused, and how I structure my own training year to be ready for events that last well beyond 24 hours.
What Is FTP vs Endurance Base Cycling; and Why Ultra Cyclists Get It Wrong
FTP, or Functional Threshold Power, is the maximum power output you can sustain for roughly 60 minutes. It’s the number that drives most training plans, races, and coffee-shop debates. Endurance base, sometimes called aerobic base or Zone 2 fitness, is something different entirely: it’s the deep aerobic capacity that allows your body to burn fat efficiently, delay glycogen depletion, and keep moving for hours and hours without collapse.
Here’s the problem: most recreational cyclists come up through event cycling or sportive riding, where FTP is king. You train to get faster over three to five hours. You push threshold intervals and measure your progress in watts per kilo. All of this is great. Until you decide to ride 400 km in a single push, attempt an Everesting, or enter a race where the winning time is measured in days, not hours.
Functional Threshold Power Explained
FTP gives you a ceiling: how hard you can go when it matters. In road racing, criteriums, and even 200 km gran fondos, a higher FTP gives a real competitive edge. The training zones are built around it: Zone 3 (tempo, 76–87% of FTP), Zone 4 (threshold, 88–100% of FTP), and Zone 5 (VO2 max, above FTP). Push these zones regularly and you get faster at sustained, hard efforts.
For ultra-distance cycling, however, you will rarely race anywhere near FTP. During my 24-hour challenge, where I covered over 630 km, my average power was well below Zone 3. Think Zone 1 to low Zone 2, with occasional pushes when terrain demanded it. FTP was almost irrelevant to that performance. What mattered was how efficiently my aerobic system could sustain output for a full day and night.
The Aerobic Base — Your Ultra-Distance Engine
The aerobic base is built at low intensity. What most training plans call Zone 2, typically 56–75% of FTP, or roughly 60–70% of maximum heart rate. At this intensity, your body preferentially burns fat for fuel. Fat is essentially unlimited. Even a lean cyclist carries enough body fat to fuel hundreds of kilometres. Glycogen, the carbohydrate stored in your muscles and liver, is limited to roughly 90–120 minutes of hard effort.
So when you’re planning to ride for 20, 24, or 36-plus hours, the ability to burn fat efficiently isn’t a nice-to-have. It’s the difference between finishing and abandoning at the roadside. A rider with a massive aerobic base can cruise at 200–220 watts while running almost entirely on fat. A rider who has trained only threshold work will hit glycogen depletion, bonk hard, and struggle to manage the inevitable nutrition challenges that come with ultra distance.
Testing FTP vs Endurance Base Cycling in the Real World
I built my solo training camps entirely around this question. Every year I head out twice; five to seven days of riding completely alone, no group, no planned route, just the bike and the mountains. Last time I was in the French Alpes. I rode six consecutive days averaging over 5,000 metres of climbing per day. Not once did I push above Zone 3. The entire camp was aerobic base work, and by the end of it I came home stronger than any threshold block had ever left me.
The Fat-Burning Advantage of Zone 2
Zone 2 training triggers specific physiological adaptations that are unique to this intensity. You grow more mitochondria per muscle fibre (mitochondrial density), improve fat oxidation at submaximal intensities, and increase cardiac stroke volume; the amount of blood your heart can pump with each beat. These changes take months, not weeks. You can’t fake them with a three-week training block, and you absolutely can’t shortcut them with threshold intervals.
As I covered in my Transcontinental Race preparation guide, the foundations of ultra-distance performance are built during months of patient, unglamorous low-intensity riding. Not in dramatic threshold sessions that feel productive but miss the specific demands of riding through the night. The riders who finish events like the TCR, PBP, or Race Around Belgium are not the riders with the biggest FTP numbers. They’re the riders with the deepest aerobic engines.
Why High-Intensity Work Can Backfire for Ultra Cyclists
I’m not saying FTP doesn’t matter. Of course it does. A higher FTP means a lower relative intensity at your ultra-distance cruising pace. If your FTP is 300 W and you’re cruising at 180 W, that’s a comfortable 60% effort. If your FTP is 200 W, that same 180 W is 90%, deep Zone 4, and you’ll blow up in three hours. So FTP is a ceiling that determines how sustainable your ultra pace actually feels.
But here’s the trap: spending too much training time chasing FTP gains, hammering intervals, doing short punchy rides, living in Zone 4, actively competes with aerobic base development. High-intensity training stress suppresses the fat-burning adaptations you’re trying to build. You end up fit for a sportive, not built for the long game. Belgian roads are not kind to equipment or to training shortcuts, and neither are 20-hour events.
How I Structure Training Around Aerobic Base Volume
My training year has a clear rhythm. From October to March, I ride enormous volumes at Zone 1 and Zone 2. My annual distance of around 30,000 km is built on months of this steady aerobic work. I keep the intensity genuinely low, low enough that I can recover day to day, and I accumulate the kind of base that supports multi-day events. These aren’t glamorous rides. They’re sometimes into gale-force winds, on rain-soaked Belgian roads that would shred a climber’s spirit. But they build something bulletproof.
As spring arrives, I introduce threshold work, but sparingly, maybe two focused sessions per week. This is the time to sharpen the FTP, layered on top of the solid aerobic foundation. In the final six to eight weeks before a major event, I dial the intensity back down, focus on recovery, and let all those adaptations consolidate. It’s a classic periodization model, but ultra-distance specific.
The Solo Training Camp Method
My two annual training camps are where the real base building happens. In the French Alps or the Dolomites or the Spanish Pyrenees, I ride for five to seven days straight, completely alone. No group pace to chase, no ego involved. I go as slowly as I need to in order to keep my heart rate in Zone 2, even on the big climbs. Some days that means ascending a serious mountain at 10–12 km/h. I don’t care. I’m building the engine, not testing it.
This method sounds boring. It really isn’t. It becomes meditative, almost spiritual. And the results speak for themselves. Every Everesting, every 300 km-plus brevet, every overnight race I’ve completed has been fuelled by this base. The Bicinglé du Ventoux, six ascents of Mont Ventoux in a single day, was possible because months of base riding had given me an aerobic system that could simply keep going when every other signal said stop. That’s what a proper endurance base does. It extends your ability to function far beyond what your FTP alone ever could.
A Practical Weekly Structure for Ultra-Distance Riders
If you’re building toward a major ultra event, here’s a base-phase structure that works in practice:
- Monday:complete rest or 30 min very easy spin
- Tuesday:2.5–3 hours Zone 2
- Wednesday:1.5–2 hours Zone 2, with 1 × 20 min threshold effort if you’re in a build phase
- Thursday:2–2.5 hours Zone 2
- Friday:rest or 45 min active recovery
- Saturday:5–8 hours Zone 2 / low Zone 3 (the long ride — keep it genuinely aerobic)
- Sunday:3–4 hours Zone 2 recovery ride
Total volume in a peak base week: 15–18 hours. The crucial rule is keeping Saturday genuinely aerobic. Not letting it drift into tempo territory just because you feel good. The moment you push past Zone 2 on the long day, you compromise recovery and delay adaptation. Patience is the hardest skill in ultra training.
Is FTP vs Endurance Base Cycling Really Worth the Debate?
Honestly? The best ultra-distance cyclists understand these aren’t opposing forces. They are a sequencing question. You build the aerobic base first, over months and years. Then you layer threshold work on top to raise your FTP ceiling. Then you taper and let it consolidate before the event. In that order.
The mistake most amateur ultra cyclists make is inverting this pyramid. They train hard all winter with high-intensity intervals, hit a great FTP number by April, sign up for a 600 km brevet in June, and wonder why they implode at kilometre 350. The answer is almost always the same: not enough base. The fitness is there for a five-hour hard ride. The durability for a 20-hour grind is simply not.
FTP vs Endurance Base Cycling: Pros, Cons, and the Verdict
FTP-focused training:
- Pros:measurable week-to-week progress; works brilliantly for road racing and sportive events; motivating short-term gains; huge library of structured plans available
- Cons:doesn’t develop the fat oxidation needed for 10-plus-hour efforts; recovery demands limit weekly volume; can lead to glycogen dependency; misses the mitochondrial adaptations essential for ultra distance
Endurance base training:
- Pros:builds durable, deep aerobic fitness; dramatically improves fat metabolism; supports high weekly training volumes; translates directly to ultra-distance performance; lower injury and burnout risk
- Cons:progress is slower and harder to see on a power meter; requires months, not weeks; can feel monotonous without variety; demands a lifestyle that allows big volume
For ultra-distance cycling, the verdict is clear. The endurance base is the foundation. The FTP work is a spice, used carefully and at the right time. Build in that order, and your ultra performances will transform.
Frequently Asked Questions
Is Zone 2 training really better than FTP intervals for ultra cycling?
For ultra-distance events lasting more than 8–10 hours, Zone 2 training is foundational and cannot be replaced by FTP intervals alone. Zone 2 builds the specific fat-oxidation capacity and mitochondrial density that power you through the night and beyond. FTP intervals are valuable but should be layered on top of an existing aerobic base, not used as a substitute for it. If you’re choosing between the two for an event over 400 km, prioritise the base every time.
How much Zone 2 training per week is needed for ultra distance cycling?
Serious ultra-distance riders typically train 12–20 hours per week, with 70–80% of that volume in Zone 2 during base phase. A practical minimum for building meaningful aerobic base is around 10 hours per week, with at least one long ride of 5–7 hours at the weekend. More volume leads to faster adaptation, but consistency over months matters more than any single week’s total.
Can I do FTP intervals while building my endurance base cycling?
Yes, but sparingly and only once a solid base is established. During a dedicated base phase, limit threshold work to one session per week at most, and only if it doesn’t compromise the volume and recovery of your Zone 2 riding. During build phase, two threshold sessions per week works well. The biggest mistake is doing too much high-intensity work too early and suppressing the aerobic adaptations you’re trying to build.
What training approach works best for events like Everesting or long brevets?
For Everesting, long brevets (300, 400, 600 km), and similar ultra events, a base-heavy training approach works best. Spend the majority of your preparation building aerobic volume at low intensity, with a 6–10 week sharpening block of moderate threshold work before the event, followed by a proper 10–14 day taper. Nutrition and pacing strategy matter as much as fitness. Training the gut to absorb calories at ultra pace is a specific skill that only long rides can develop.
How long does it take to build an aerobic base for ultra distance cycling?
Building a meaningful aerobic base takes a minimum of 3–6 months of consistent, high-volume Zone 2 training. Significant mitochondrial adaptations, the kind that genuinely transform ultra-distance performance, take 6–12 months. This is why most experienced ultra cyclists view base building as a year-round commitment rather than a seasonal phase. The riders who complete events like PBP or Transcontinental Race reliably are the ones who have been building their aerobic engines for years, not months.
Have you tried training specifically for ultra distance? Does Zone 2 dominate your training plan, or do you still lean on threshold intervals? Drop a comment below. I’d love to hear your experience.
