A beginner's guide to cycling power zones
Most cyclists who train by feel make the same mistake: riding too hard on easy days and too easy on hard days. A power meter fixes that by stripping away the guesswork and showing you exactly how hard you’re working in real time.
What is FTP and why does it matter?
FTP stands for Functional Threshold Power. It’s the maximum average power, measured in watts, that you can sustain for roughly an hour. Think of it as the line between efforts you can maintain and efforts that will eventually force you to stop. Everything in power-based training revolves around this number.
Your FTP is personal. A recreational cyclist might have an FTP of 180 watts. A competitive age-group triathlete might sit around 250-280. A pro could be well above 350. The number itself doesn’t matter much on its own. What matters is that it gives you anchor points for building your training zones.
FTP also changes over time. As you get fitter, it goes up. If you take time off, it drops. Testing it periodically (every 6-8 weeks during a training block) keeps your zones calibrated so you’re actually training at the right intensities.
How to test your FTP
There are two common methods, and both work fine. Pick whichever one you’ll actually do consistently.
The 20-minute test. Warm up for 15-20 minutes, including a few short efforts to open your legs up. Then ride as hard as you can sustain for exactly 20 minutes. Your FTP is approximately 95% of your average power during that 20-minute effort. So if you averaged 210 watts, your estimated FTP is about 200 watts. The 5% discount accounts for the fact that most people can push slightly harder for 20 minutes than they can hold for a full hour.
This test is straightforward but it requires good pacing. Go out too hard in the first five minutes and you’ll blow up. Too conservative and you’ll underestimate your FTP. It takes a few attempts to get the pacing right.
The ramp test. You start at a low wattage and the resistance increases by a set amount (usually 20 watts) every minute until you can’t hold the target anymore. Your FTP is estimated as 75% of the highest one-minute power you achieved. Most smart trainers and apps like Zwift, TrainerRoad, or Wahoo SYSTM have ramp tests built in.
The ramp test is easier to execute because there’s no pacing strategy. You just keep going until you can’t. The downside is that it tends to overestimate FTP for people with strong anaerobic capacity and underestimate it for diesel-engine types who can grind forever at steady state. If your ramp test FTP feels too high when you try to do workouts based on it, knock it down 3-5%.
If you’re doing these tests on a smart trainer, ERG mode makes the ramp test particularly easy to execute since the resistance adjusts automatically.
The 7 power zones
Once you have your FTP, you can calculate your training zones. Different coaches use slightly different zone models, but the most widely used is Andrew Coggan’s seven-zone system. Here’s how they break down:
| Zone | Name | % of FTP | What it feels like |
|---|---|---|---|
| 1 | Active Recovery | < 55% | Barely pedaling. Feels like you’re doing nothing. |
| 2 | Endurance | 56-75% | Conversational pace. Could ride here for hours. |
| 3 | Tempo | 76-90% | Comfortably uncomfortable. Can talk in short sentences. |
| 4 | Threshold | 91-105% | Hard. Conversation is one or two words at a time. |
| 5 | VO2max | 106-120% | Very hard. 3-8 minute efforts. You want it to stop. |
| 6 | Anaerobic | 121-150% | All out for 30 seconds to 2 minutes. Burning legs. |
| 7 | Neuromuscular | Max effort | Full sprints. Under 30 seconds. Everything you have. |
For triathlon training, you’ll spend the vast majority of your time in zones 1-4. Zone 2 is where your aerobic base gets built. Zone 4 is where your race fitness sharpens. Zones 5-7 matter too, but in smaller doses during specific phases of training.
Why power beats heart rate for cycling
I used to train by heart rate and thought that was good enough. It’s not bad. But power has real advantages for cycling that are worth understanding.
Heart rate lags. When you start a hard effort, your power output changes instantly. Your heart rate takes 30-90 seconds to catch up. For short intervals, this makes heart rate almost useless as a real-time guide. By the time your heart rate reflects the effort, the interval might be half over.
Cardiac drift is real, too. On a long ride, your heart rate gradually creeps up even if your effort stays the same. After 90 minutes at the same power, your heart rate might be 10-15 beats higher than it was at the start. If you’re pacing by heart rate alone, you’d slow down to keep the number in check when you don’t necessarily need to. Power shows you the actual work being done regardless of what your heart is doing.
Then there’s all the external stuff. Caffeine, heat, dehydration, sleep quality, stress. All of these shift your heart rate without changing your actual fitness or the work you’re doing. Power doesn’t care about any of that. 200 watts is 200 watts whether you slept eight hours or five.
That said, heart rate data is still valuable as a secondary metric. Comparing heart rate to power over time tells you a lot about your fitness trajectory. If the same power output is producing a lower heart rate than it did two months ago, you’re getting fitter.
Using zones in structured workouts
Once you know your zones, you can build workouts with specific purposes instead of just riding around at whatever effort feels right that day.
A typical endurance ride might be two hours in zone 2. The goal is building aerobic capacity without accumulating fatigue. These rides should feel easy. Really easy. Almost too easy. That’s the point.
A threshold workout might look like 3x12 minutes at zone 4 with 5 minutes of recovery between intervals. This builds your ability to sustain hard efforts, which directly translates to faster bike splits on race day.
A VO2max session could be 5x4 minutes at zone 5 with 4 minutes recovery. These are brutal but effective at raising your ceiling.
The point is that each workout has a target zone and a purpose. You’re not just going out and riding medium-hard and hoping for the best.
The zone 3 trap
This is the single most common mistake in triathlon training. Zone 3, tempo, is the danger zone. It feels productive. You’re working. You’re sweating. Your legs are tired when you get home. But it’s too hard to build real aerobic endurance (that’s zone 2’s job) and too easy to drive meaningful threshold or VO2max adaptations.
Coaches call it “no man’s land” or “the grey zone” and for good reason. If you spend most of your training time in zone 3, you get moderately tired all the time without getting measurably faster. You accumulate fatigue without accumulating fitness.
The fix is polarized or pyramidal training. Roughly 80% of your riding should be in zones 1-2 (actually easy) and 20% should be at zone 4 or above (actually hard). Very little should land in zone 3. This felt wrong to me at first. Easy rides felt like I was wasting time. But after two months of actually riding easy on easy days, my FTP went up 15 watts. More than it had in the previous six months of riding zone 3 all the time.
Learning to ride easy is the hard part
Zone 2 feels painfully slow at first. You’ll get passed by casual riders and wonder if your cycling computer is broken. It takes a few weeks to get comfortable with how easy it should feel.
But stick with it. What happens is that your heart rate at the same power starts dropping, your endurance on long rides improves, and when you do go hard on interval days, you actually have the energy to push into zones 4 and 5 instead of limping through them because yesterday’s “easy” ride was actually tempo.
Getting started
You don’t need to overthink this. Test your FTP with either the 20-minute test or a ramp test. Calculate your zones using the percentages above. Then start paying attention to which zone you’re in during every ride. That awareness alone will change how you train.
The biggest shift is mental. Accepting that easy should feel easy and hard should feel hard. Most of us naturally default to medium effort because it feels like we’re doing something without the suffering of real intensity. Training by power zones breaks that habit, and your fitness benefits when it does.
