The WattPlan Podcast · Episode 15 · 9 min
What are power zones actually for?
Next episodes: What is FTP, and is your test telling the truth? · How do you set heart rate zones, and when do you trust them? · Is Zone 2 worth the hours?
Read the transcript
James. Hello and welcome to the WattPlan Podcast. I'm James. I juggle a family and a day job, sneak the odd podium when the fast lads stay at home, build WattPlan in the gaps, and read sports science the way other people read thrillers. This week, power zones. Seven of them, all hung off one number. What are they actually for, and do I need all seven? Lyra's our AI research voice, and every study she mentions is linked in the show notes.
Lyra. You need to know which one you're in far more than you need all seven. Power zones are bands of effort, each one a slice of your FTP, the power you could hold for about an hour. They give you a shared language, so an easy ride on Tuesday is the same easy as on Saturday. The boundaries are conventions. The point is landing in the right band for the job.
James. So seven zones, seven different kinds of session I'm meant to be doing every week?
Lyra. No, and that's the trap. Most riders use three or four of them in a normal week. Think of the seven as a map. You don't visit every town on it, you just need to know where you are.
James. Fair. Start me at the bottom, then.
Lyra. Zone 1 is active recovery, anything under about 55 percent of FTP. Spinning your legs, chatting, no real stress. Zone 2 is endurance, from there up to 75 percent. That's where the aerobic base gets built, more mitochondria, better use of fat, and you can hold it for hours.
James. Give me that in watts. Say a 250 watt FTP.
Lyra. Then Zone 2 is roughly 140 to 188 watts. For a lot of riders the top of that feels suspiciously easy, which is exactly why they ride over it.
James. Guilty. And above that?
Lyra. Zone 3, tempo, runs up to 90 percent. Conversation gets choppy, and you could hold it for an hour or three. Then Zone 4, threshold, carries on up to 105 percent. That's where FTP lives, the hard, steady effort you can keep up for twenty minutes to an hour.
James. Where does sweet spot sit in all this? Because it's not one of the seven, is it?
Lyra. It isn't. Sweet spot is 88 to 94 percent, so it straddles the top of tempo and the bottom of threshold. WattPlan treats it as its own band, because so much early hard work in a plan sits there.
James. And the top three? The ones that hurt.
Lyra. Zone 5 is VO2max, up to 120 percent, efforts of three to eight minutes that push your oxygen ceiling. VO2max being the most oxygen you can use in a minute. Zone 6 is anaerobic, up to 150 percent, half a minute to a few minutes of punch for attacks. Zone 7 is everything above, sprints of a few seconds.
James. Okay, here's the thing I actually want to know. How much time should I spend in each? Because I suspect my honest answer is mostly Zone 3, by accident.
Lyra. You'd have plenty of company. We looked at two studies for this. The first is Stephen Seiler's 2010 review in the International Journal of Sports Physiology and Performance. He pulled together descriptive studies of national and international endurance competitors, and they converged on a pattern. About four in five sessions at low intensity, about one in five dominated by hard work. [1]
James. Four in five of the hours?
Lyra. Of the sessions, not the hours. It's the detail that gets lost every time someone quotes eighty twenty. And the same review found no convincing evidence that piling more hard work onto people who were already well trained gave them long term gains.
James. Right, but these are people training ten, twelve times a week. Surely that doesn't really apply to someone with a job and five hours?
Lyra. That's the right objection, and it's what the second study helps with. A 2025 network meta-analysis in Sports Medicine went back to the individual data from 13 studies and 348 endurance athletes, both recreational and competitive. It compared polarised training, mostly easy with a little very hard, against pyramidal, which keeps a bit more in the middle. For VO2max and time trial results, no real difference overall. [2]
James. So the whole online fight about the middle zone is about nothing?
Lyra. Not nothing. The split by level was interesting. Competitive riders tended to gain more VO2max from polarised training, and recreational riders did a little better with pyramidal. So Zone 3 isn't poison. The real problem is drifting into it on rides that were meant to be easy, until your easy days aren't easy and your hard days aren't hard.
James. So the zones are less about the exact percentages and more about protecting the difference between easy and hard.
Lyra. Yes. And that's how WattPlan uses them. The hard sessions are sweet spot, threshold and VO2max, never more than two in a week and never back to back, and the rest is easy. Zone 6 and 7 sessions sit in the library, but a plan won't put them in your week.
James. Which is interesting if you race, because races get decided up there.
Lyra. If you race, that's true, and the top zones matter more to you than to most. But the 2025 analysis is a hint about VO2max work, not proof that sprint sessions win races. A road race plan's build weeks carry at most one VO2max session, so race-specific punch is something you'd add knowingly, not by default.
James. And if you're new to structured training and all this is a bit much?
Lyra. Then forget seven zones for now and think easy, steady and hard. Ride a WattPlan workout by feel and every step carries an effort out of ten, with a talk test to go with it. Zone 2 is full sentences. Sweet spot is a few words at a time. That's enough to ride a plan well.
James. Do the zones change as I get fitter? I've had the same numbers for a year.
Lyra. Only when your FTP changes. If a workout you ride in WattPlan's player suggests your FTP is at least three percent higher, it asks whether you want to update it, and every zone moves with it. It never changes your FTP on its own, which matters if you train with power, because a stale FTP puts every zone in the wrong place.
James. And heart rate? My mate swears by it.
Lyra. Heart rate is useful, but it lags. On a long steady effort it settles and tells you plenty. On a two minute interval it's still climbing when you've finished. So use power to set the effort and heart rate to check how your body is coping with it, especially on hot days.
James. What can't the studies tell us here?
Lyra. Quite a bit. Seiler counted sessions in elite competitors, not riders like us. The 2025 analysis was mostly men. And the zone boundaries themselves are conventions built on percentages of FTP, not lines your body draws. Nobody has tested whether Zone 2 should stop at 75 or 77 percent for you, so treat the edges as soft. A few watts either side isn't worth worrying about.
James. Right. Give me something to do before the weekend.
Lyra. Three things. One, open You, then Metrics, check your FTP is current, and write down the top of your Zone 2. Two, ride your next easy ride under that number, climbs included. Three, look back at last week and count the rides that were meant to be easy but crept into tempo. Next time, ride those properly easy.
James. So, one number on a sticky note, and stop letting my easy rides wander. That's honestly the bit I get wrong.
Lyra. Most people do. The zones aren't there to make every ride precise. They're there to make sure your easy rides are easy enough that your hard ones can actually be hard.
Lyra. The full article and every study we mentioned are on the WattPlan blog, linked in the show notes. And if you've enjoyed this, follow the WattPlan Podcast wherever you're listening, so you don't miss the next one.
James. And if you want a plan built around the time you've actually got, get WattPlan on the App Store or Google Play. Thanks for listening.
Voices produced with ElevenLabs. James's voice is a clone of his own, Lyra is an AI voice, and James reviews every episode.
Power zones in cycling split your effort into seven bands by share of FTP, from active recovery below 55% to neuromuscular power above 150%. At an FTP of 250 W, endurance is 138 to 187 W and threshold 226 to 262 W. Competitive endurance riders do about 80% of their sessions at low intensity, in Seiler's 2010 review.
What are the 7 power zones in cycling?
The seven zones are the levels Allen and Coggan set out alongside their 20-minute FTP test, and they are the zones WattPlan uses. Each is a share of FTP, so the table reads the same for any rider, and the watts columns show what the bands mean at three common FTPs.
| Zone | Name | Share of FTP | At 200 W FTP | At 250 W | At 300 W |
|---|---|---|---|---|---|
| 1 | Active Recovery | up to 55% | up to 110 W | up to 137 W | up to 165 W |
| 2 | Endurance | 56 to 75% | 111 to 150 W | 138 to 187 W | 166 to 225 W |
| 3 | Tempo | 76 to 90% | 151 to 180 W | 188 to 225 W | 226 to 270 W |
| 4 | Threshold | 91 to 105% | 181 to 210 W | 226 to 262 W | 271 to 315 W |
| 5 | VO2 Max | 106 to 120% | 211 to 240 W | 263 to 300 W | 316 to 360 W |
| 6 | Anaerobic | 121 to 150% | 241 to 300 W | 301 to 375 W | 361 to 450 W |
| 7 | Neuromuscular | above 150% | above 300 W | above 375 W | above 450 W |
The upper bound of each zone is inclusive, so exactly 75% of FTP is still endurance and exactly 105% is still threshold. The watts columns are the whole watts the app and the FTP calculator assign to each zone, so no watt falls between two zones. Sweet spot is not a zone of its own. It is the band from 88 to 94% of FTP, across the top of tempo and the bottom of threshold, and the FTP calculator lists it as a row of its own.
How long each zone can be held is mostly convention, with one exception. Sitko and colleagues tested how long road cyclists could ride at the FTP from their 20-minute test in 2022, and the median was 35 minutes for recreationally trained riders, 42 for trained, 47 for well-trained and 51 for professionals. An hour at zone 4 is close to true for a professional, and 35 minutes is nearer the mark for most of us.
How do you calculate power zones from FTP?
Multiply your FTP by each zone's top boundary and round down. At 250 W, 55% is 137.5, so recovery ends at 137 W and endurance starts at 138 W, and 75% is 187.5, so endurance ends at 187 W. The FTP calculator does this for any FTP you enter and prints the zones in watts, and the WattPlan app sets every workout step as a share of FTP, so a new FTP moves every target at once. If you don't have an FTP yet, what FTP is covers the 20-minute and ramp tests.
Zones only move when your FTP does, so retest when threshold sessions start to feel like tempo.
What does each zone train?
Zone 1 is recovery, warm-up and the rest between efforts. Zone 2 is the aerobic base, the long rides and the easy days, and most of your riding. Our zone 2 training guide covers the dose. Zone 3 is tempo, sustained but controllable, with sweet spot at its top end. Zone 4 raises the power you can hold for an hour, with long blocks at or just under FTP, set out in our threshold intervals guide. Zone 5 is the VO2max zone, efforts of a few minutes that raise your aerobic ceiling, covered in the VO2max intervals guide. Zones 6 and 7 are the attacks and the sprints.
WattPlan's library is built along the same lines, with 21 endurance workouts, 18 sweet spot workouts, 12 threshold workouts, 10 VO2 max workouts and 9 anaerobic workouts, plus 4 recovery spins and 3 tests. The plan generator counts sweet spot, threshold, VO2 max, anaerobic, interval and test sessions as the hard days of a week, and everything else as easy.
How much time should you spend in each zone?
Most of it in zones 1 and 2. Seiler reviewed the training of nationally and internationally competitive endurance sportspeople in 2010 and found that those training 10 to 13 times a week do about 80% of their sessions at low intensity, around 2 mmol/L of blood lactate, and about 20% at high intensity, with intervals at about 90% of VO2max. Adding more intervals to already well-trained riders did not convincingly improve their performance in the studies he reviewed.
Stöggl and Sperlich tested four distributions head to head in 2014 across 48 well-trained runners, cyclists, triathletes and cross-country skiers over nine weeks. The polarised group gained the most.
| Group | Low intensity | Threshold | High intensity | Change in VO2peak | Change in time to exhaustion |
|---|---|---|---|---|---|
| Polarised | 68% | 6% | 26% | +11.7% | +17.4% |
| High-intensity intervals | 43% | 0% | 57% | +4.8% | +8.8% |
| Threshold | 46% | 54% | 0% | no significant change | +6.2%, not significant |
| High volume | 83% | 16% | 1% | no significant change | +8.0%, not significant |
The threshold group, with more than half its sessions between 3 and 5 mmol/L of lactate, gained nothing significant in VO2peak over nine weeks.
The newer pooled data is less clear cut for amateurs. A network meta-analysis led by Rosenblat in 2025 pooled individual data from 13 studies and 348 trained endurance participants, 296 men and 52 women, of whom 150 were recreational and 198 competitive. Polarised and pyramidal plans, which keep most time easy but include more tempo and threshold, did not differ on VO2max or time trial performance, and polarised did not beat any other distribution overall. Competitive participants gained more VO2max from polarised, recreational ones from pyramidal. Our view at WattPlan is that a time-limited amateur does well on a pyramid, with most riding in zone 2, one sweet spot or threshold session and one VO2max session in a hard week, and that zone 3 should come from those sessions rather than from a long ride ridden too hard.
How many hard rides a week?
Two in a normal week, one when you are tired, none in a recovery week. Stöggl and Sperlich's polarised group did about a quarter of its sessions at high intensity, which on four or five rides a week is one or two. WattPlan's plan generator gives one hard day a week to a beginner, to anyone riding fewer than four days or under four hours, and in a taper, two hard days otherwise, and none in a recovery week.
Can zone 2 improve VO2max?
Yes, slowly. MacInnis and Gibala reviewed the evidence in 2017 and found that intervals and moderate continuous training both produce the classic adaptations, a higher VO2max and more mitochondria, but high-intensity intervals raise VO2max more for a given volume of training, and sprint intervals match continuous training with far less volume. In Stöggl and Sperlich's trial the high volume group, at 83% low intensity, did not significantly raise its VO2peak in nine weeks, while the polarised group raised it 11.7%. Zone 2 builds the base, and zone 5 moves the ceiling.
What are the heart rate zones for cycling?
Five bands as a share of your threshold heart rate, matched to the first five power zones. Endurance in watts, 56 to 75% of FTP, is endurance in beats, 69 to 83% of threshold heart rate, and WattPlan uses that one mapping in the player, on your Garmin or Wahoo and in the Coach. Our heart rate zones guide has the beats per minute at four thresholds and the 30-minute test to find yours.
What to do this week
- Test or confirm your FTP, then write out your seven zones in watts from the table or the FTP calculator.
- Ride your long ride and easy days at or below 75% of FTP and check the average afterwards.
- Put one sweet spot or threshold session and one VO2max session in the week, with a day between them.
- Count the time you spent in zone 3 on the easy days, and if it is more than a few minutes, ride them easier next week.
- If you are building to a sportive, pick a training plan for the event so the zones and the hard days are set for you.
What we don't know yet
The seven boundaries are a coaching convention, and no trial we found has tested 75% of FTP against a neighbouring edge of endurance. Stöggl and Sperlich studied 48 well-trained people split four ways over nine weeks, so the size of the polarised advantage in amateurs on a few hours a week is unmeasured. The Rosenblat analysis classified training by time in heart rate zone, and its recreational group was fitter than most riders starting out.
Sources
- What is best practice for training intensity and duration distribution in endurance athletes?, International Journal of Sports Physiology and Performance
- Which Training Intensity Distribution Intervention will Produce the Greatest Improvements in Maximal Oxygen Uptake and Time-Trial Performance in Endurance Athletes? A Systematic Review and Network Meta-analysis of Individual Participant Data, Sports Medicine
- Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training, Frontiers in Physiology
- Physiological adaptations to interval training and the role of exercise intensity, The Journal of Physiology
- Time to exhaustion at estimated functional threshold power in road cyclists of different performance levels, Journal of Science and Medicine in Sport