Last reviewed 28 October 2026
What Zone 2 is
In a power-based five- or seven-zone model, Zone 2 (endurance) is roughly 56 to 75% of FTP. By heart rate it is a little below the first ventilatory threshold: you can talk in full sentences, breathing is relaxed, and the effort feels like you could keep it up for a very long time.
Zone 2 is a range, not a single number. Riding at the bottom of it is easier to recover from; the top of it overlaps with ultra race pace. Most long training rides sit in the middle, around 65 to 70% of FTP.
Why it matters for long events
Steady endurance riding builds the things that let you ride for a whole day: more mitochondria and capillaries in the working muscles, better fat oxidation so glycogen lasts longer, and a heart that pumps more blood with each beat. It also trains the less glamorous parts: your back, neck and contact points, your fueling habits and your patience.
Because it is relatively easy, you can do a lot of it and still recover for the harder sessions. That volume is what builds durability.
How much Zone 2
Studies of endurance athletes tend to find that most of their training, often around three-quarters or more of their time, is at low intensity, with a smaller share at threshold and above. For ultra riders, that low-intensity share is usually even higher.
- One long ride a week is the core. Build it gradually towards 4 to 6 hours, depending on the event.
- Shorter steady rides of 1 to 2 hours fill the rest of the week.
- One or two harder sessions (sweet spot, tempo or durability work) raise the ceiling. Keep the easy days easy so these can be done well.
Doing it well
- Ride it steady. Indoors, ERG mode keeps you in the zone without surges. Outdoors, ease off on climbs rather than chasing a heart-rate number up them.
- Fuel it. Eat on long Zone 2 rides as you would in an event. It trains the gut and keeps quality high in the final hour.
- Watch decoupling. On a long steady ride, compare power to heart rate in the first and second halves. Drift below about 5% is a sign the base is solid. MeepMeep shows Pw:HR decoupling for steady rides.
- Vary cadence. Spend some time high and some low so the long hours are not identical.
Questions
What percentage of FTP is Zone 2?
In the common power-zone model, Zone 2 is about 56 to 75% of FTP. Most long endurance rides for ultra training sit around 65 to 70%.
Is Zone 2 training enough for an ultra?
It is the foundation, but most riders also benefit from one or two harder sessions a week, such as sweet spot, tempo and efforts after a long pre-load, to raise their ceiling and train durability.
Can I do Zone 2 training indoors?
Yes. ERG mode makes indoor Zone 2 very precise. Many riders do their midweek endurance rides indoors and keep the longest ride outdoors when they can.