Power Zones Calculator

Coggan's seven zones reflect the physiologically distinct training intensities identified in exercise science research. Each zone targets a different energy system or adaptation: Zone 1 promotes active recovery and blood flow, Zone 2 builds aerobic base and fat oxidation, Zone 3 develops muscular endurance, Zone 4 directly stimulates FTP improvement, Zone 5 raises maximal oxygen uptake, Zone 6 builds short anaerobic power, and Zone 7 develops peak neuromuscular force. Seven zones give coaches and athletes a precise language for prescribing workouts.

Zone 2 (56–75% of FTP) is the foundation of aerobic training. Long Zone 2 rides — typically 90 minutes to 4+ hours — build mitochondrial density, improve fat oxidation efficiency, and develop the cardiovascular base that allows you to handle more intensive training later. Many professionals spend 70–80% of their total training volume here. The key is to keep the effort genuinely easy, not 'comfortable but pushing' — if you cannot hold a full conversation, you are probably above Zone 2.

Zone 4 (91–105% of FTP) directly targets your lactate threshold, the power level where lactate begins to accumulate faster than it can be cleared. Sustained efforts in Zone 4 — typically 10 to 30-minute intervals — force your body to become more efficient at clearing lactate and sustaining high muscle recruitment patterns. Over weeks and months this pushes the threshold higher, meaning you can sustain more power before accumulation becomes limiting. Zone 4 is demanding but not all-out, which makes it repeatable across a training week.

No — and trying to hit all zones equally is a recipe for chronic fatigue. Zone emphasis should match your training phase and target event. Base building phases heavily weight Zone 2 with minimal high-intensity work. Build phases introduce more Zone 4–5 intensity. Peak phases sharpen Zone 5–6 for race-specific demands. Neuromuscular Zone 7 sprints are only important for track cyclists, criterium racers, and riders who need explosive finishing speed.

Always recalculate zones immediately after a new FTP test. Using outdated zones makes workouts either too easy (if FTP has improved) or dangerously hard (if you entered the previous season deconditioned). Also recalculate if your training consistently feels out of sync — interval completion rates and RPE are useful proxies even between formal tests.

Zone 3 (76–90% of FTP) is moderately hard but sustainable for 60–90 minutes. It builds muscular endurance and economy but does not drive the same threshold adaptation as Zone 4. Many athletes train too much in Zone 3 because it feels hard without feeling punishing, but it does not produce the aerobic base gains of Zone 2 or the threshold gains of Zone 4. Deliberately choosing between the two is more productive than defaulting to the middle.

Zone 5 (106–120% of FTP) targets your maximal oxygen uptake — the absolute ceiling of your aerobic engine. Short efforts of 3 to 8 minutes at Zone 5 intensity force maximum cardiac output and ventilation, stimulating cardiac chamber growth and improving oxygen delivery. Zone 5 efforts are much harder to recover from than Zone 4 and should be introduced carefully, especially for less experienced athletes. A common structure is 4–6 x 4 minutes at Zone 5 with equal recovery.

Power zones as defined here are cycling-specific because they are calculated from cycling FTP. Running uses its own pace-based or running-power zones (if you have a running power meter). The underlying training philosophy — polarizing intensity between low and high with minimal junk miles — translates across sports, but the specific percentages do not carry over between disciplines.