Guides
Understanding Training Zones on the Turbo (Coach's Guide)
The short answer
- Training zones split your effort into bands (usually Coggan's seven) so you train the right energy system on purpose, not by feel.
- Set power zones from your FTP (functional threshold power); set heart rate zones from your threshold heart rate, not your max.
- Zone 2 builds aerobic base, sweet spot and threshold build sustainable power, and Zone 5 and above sharpen your top end.
- On the turbo, power zones beat heart rate zones for short, hard efforts because power responds instantly and heart rate lags.
- Retest your FTP every six to eight weeks, or your zones drift out of date and your sessions stop landing.
Training zones are the fix when you finish a turbo session unsure whether it did anything. A training zone is a band of effort, measured by power or heart rate, that targets one part of your fitness. Easy riding builds your aerobic base, hard efforts sharpen your top end, and the middle bands build the sustainable power that wins club runs and sportives. Set your zones off your FTP, train in the right one on purpose, and every session has a job.
This is the version of the zones talk I give every new rider I coach, stripped of jargon: the bands that matter, how to set them off your FTP, and where most people go wrong.
What are training zones?
Training zones break the full range of cycling effort into bands. Each band stresses a different physiological system, so by choosing a zone you choose what you are training. Ride too easy and you build base but never raw power. Ride everything hard and you get tired without getting fast. Zones stop you living in the “grey zone” in the middle, which is the single most common mistake I see in riders who train hard but plateau.
The most widely used system is Dr Andrew Coggan’s seven-zone power model. It is the default in TrainerRoad, Zwift’s workout structures and most coaching software, so it is the one worth learning.
The Coggan 7-zone power model
Each power zone is defined as a percentage of your FTP. Set your FTP correctly and the table below gives you every zone in watts. The numbers are the standard Coggan bands.
| Zone | Name | % of FTP | What it trains | How it should feel |
|---|---|---|---|---|
| 1 | Active recovery | Under 56% | Recovery, flushing the legs | Easy spin, full conversation |
| 2 | Endurance | 56 to 75% | Aerobic base, fat use | All-day pace, can chat |
| 3 | Tempo | 76 to 90% | Aerobic strength | Working, short sentences |
| 4 | Threshold | 91 to 105% | Sustainable power (FTP) | Hard, a word or two only |
| 5 | VO2 max | 106 to 120% | Top-end aerobic power | Very hard, no talking |
| 6 | Anaerobic | 121 to 150% | Short, sharp efforts | Burning, gasping |
| 7 | Neuromuscular | Over 150% | Sprint and peak power | Maximal, seconds only |
A worked example: if your FTP is 250 W, your Zone 2 is roughly 140 to 188 W, your threshold zone is 228 to 263 W, and your VO2 max work sits at 265 to 300 W. Punch your own FTP into those percentages and write the watts on a sticky note by the trainer.
The band that gets the least attention but earns the most for time-crunched riders sits between tempo and threshold. That is sweet spot, and it deserves its own treatment: see my guide on what sweet spot training on a turbo actually is for why it is the workhorse of a busy winter.
How to set your power zones from FTP
FTP, functional threshold power, is the highest power you can hold roughly steady for about an hour. Everything above hangs off it, so getting it right matters more than any kit you own.
- Warm up properly. Ten to fifteen minutes building from easy to tempo, with a couple of short hard bursts to open the legs.
- Do the test. The 20-minute test is the practical standard: ride as hard as you can sustain for a flat 20 minutes, take your average power, and multiply by 0.95. The 5 percent haircut accounts for the test being shorter than a true hour.
- Set your zones. Apply the percentage bands from the table above to that FTP figure. Most apps do this for you the moment you enter the number.
- Re-test every six to eight weeks. As you get fitter your FTP rises and your old zones become too easy. Stale zones are the quiet reason a plan stops working.
If you want to understand what the watts on your screen actually represent before you test, read understanding power readings on your turbo trainer first. A smart trainer’s ERG mode makes holding each zone far easier, but it is only as good as the power figure it reports, so a trainer you trust matters for zone work.
Power zones versus heart rate zones
You can build zones off heart rate instead of power, and for endurance riders on a budget that is perfectly valid. But on the turbo, for anything structured, power wins. Here is the honest trade-off.
| Power zones | Heart rate zones | |
|---|---|---|
| Responds to effort | Instantly | Lags 1 to 3 minutes |
| Good for short intervals | Yes | No, the interval is over before HR catches up |
| Drifts over a session | No | Yes, creeps up at steady power (cardiac drift) |
| Affected by heat, sleep, caffeine | No | Yes, noticeably |
| Needs | Power meter or smart trainer | A chest strap |
| Cost | Higher | Low |
The coaching lesson is simple: power is the number you can trust to act on second by second, because it reflects the work you are doing right now rather than your body’s delayed response to it. Heart rate is still useful, just for a different job. I use it as a fatigue gauge. If a rider’s heart rate is 8 to 10 beats higher than normal for the same Zone 2 power, that is the body asking to back off regardless of what the watts say.
For setting heart rate zones, base them on your lactate threshold heart rate (roughly your average HR over the last 20 minutes of that FTP test), not your maximum. Threshold-based heart rate zones map far more usefully onto training than the old “220 minus age” max-based formulas, which are wildly inaccurate for most people.
How beginners should simplify the zones
Seven zones is the right model, but it is not where a beginner should start. For your first few months, collapse the system into three buckets:
- Easy (Zone 2): the bulk of your riding. If you can hold a conversation, you are there.
- Moderate (sweet spot to threshold, Zones 3 to 4): your “comfortably hard” work, a few minutes at a time.
- Hard (Zone 5 and above): short, properly uncomfortable efforts where talking is impossible.
Get comfortable feeling the difference between those three and the finer bands will make sense later. New riders also tend to do too much, too soon: my guide on how often beginners should use a turbo trainer sets a realistic starting frequency so you actually recover between hard days.
Putting zones into a week
Knowing the zones is half the job. The other half is arranging them across a week so the hard days are hard, the easy days are genuinely easy, and you recover enough to repeat it. A typical week for a club rider with three or four turbo sessions might be: one Zone 2 endurance ride, one sweet spot or threshold session, one VO2 or interval session, and an optional easy spin. The exact balance depends on your goal and your time.
I have laid the whole structure out, with example sessions per zone, in my guide to creating a weekly turbo training plan. Read the zones here, then build the week there.
The bottom line
Training zones turn a turbo session from “I rode for an hour” into “I trained my aerobic base” or “I sharpened my threshold”. Set your FTP honestly, apply Coggan’s seven bands, coach off power for the hard stuff and use heart rate as a fatigue check, and retest every six to eight weeks. Do that and the turbo stops being a grind and starts being a tool. Keep it simple at first, get the three broad efforts right, and add precision as your fitness and your structure mature.