If you train with a power meter, zones are everything. Each one targets a different energy system and produces different adaptations. Training in Zone 4 when your workout calls for Zone 2 isn't "close enough." It's training the wrong system entirely.
All zones are percentages of your FTP. If you don't know yours, test it first.
Zone 1: Active Recovery (below 55% FTP)
Barely pedaling. It feels like nothing. That's the point. Zone 1 promotes blood flow and clears metabolites without adding training stress. Use it for recovery rides, warmups, and cooldowns.
250W FTP? Zone 1 is below 137W.
Zone 2: Endurance (56-75% FTP)
The most important zone in cycling. Zone 2 builds your aerobic engine: mitochondria, capillaries, fat oxidation, cardiac efficiency. You should be able to hold a conversation. If you can't talk, you're above Zone 2.
This is where 70-80% of your total training time should live. Long Zone 2 rides aren't exciting. Nobody posts them on Instagram. But they're the foundation of every fast cyclist on the planet.
250W FTP? Zone 2 is 140-187W.
Zone 3: Tempo (76-90% FTP)
The "no man's land." Harder than endurance but below threshold. Useful for group rides, long climbs, and gran fondo pacing. The problem is that most riders accidentally live here. They think they're doing Zone 2 but they can't resist pushing the pace.
If Zone 3 dominates your training distribution, you're working hard and going nowhere. Use it deliberately or not at all.
250W FTP? Zone 3 is 190-225W.
Zone 4: Lactate Threshold (91-105% FTP)
Your money zone for FTP development. Efforts here teach your body to process and clear lactate more efficiently. The classic 2x20 min at 100% FTP lives here.
Zone 4 feels like concentrated, manageable suffering. You can't talk, but you can maintain focus and form. Sustainable for 20-60 minutes in trained riders.
250W FTP? Zone 4 is 227-262W.
Zone 5: VO2max (106-120% FTP)
This is where you raise the ceiling. Hard, gasping intervals lasting 3-8 minutes that improve your maximum rate of oxygen consumption. Your legs burn, your lungs burn, and you want to quit. That's normal.
250W FTP? Zone 5 is 265-300W.
Zone 6: Anaerobic Capacity (121-150% FTP)
Efforts lasting 30 seconds to 2 minutes. High lactate, high pain. Critical for racing: attacking on climbs, bridging gaps, responding to surges.
Zone 7: Neuromuscular Power (max effort)
All-out sprinting, 5-15 seconds. Limited by the neuromuscular system, not metabolism. No percentage of FTP applies. Just go as hard as you physically can.
How time distributes across zones
A well-structured plan, regardless of phase, keeps most time in Zone 1-2:
- Base: 80-85% Zone 1-2, some Zone 3-4, minimal Zone 5+
- Build: 75% Zone 1-2, 15% Zone 4-5, 10% other
- Race: 70% Zone 1-2, 15% Zone 4-5, 10% Zone 6-7
The common thread: most of your time should always be easy.
The point
Zones aren't just numbers on a screen. They're physiological targets. When your workout says "20 minutes at Zone 4," it's asking your body to perform a specific metabolic task. Riding 10% above or below that target changes which systems get trained. Precision matters. That's why knowing your FTP matters. That's why zones matter.