Heart rate zones
six methods · bpmSix systems against one axis, every band labelled in bpm, with the threshold line running through them. None is the right answer — they disagree about where your effort sits, and that disagreement is the point. Tap any ⓘ for how a method is built, what it is good at, and where it fails.
Power zones
four methods · wattsThe same treatment for watts. Note the contrast with heart rate: power systems mostly agree, because they share one anchor and one percentage table. What varies is how many bands you keep and whether the anchor itself was set correctly — which is why the uncorrected 20-minute row is here.
Finding your anchors
Lactate threshold HR
Friel's field test. Ride hard and alone; group dynamics and terrain both corrupt it.
LTHR = mean HR of minutes 11–30.
Discard the first 10 — HR is still climbing.
Maximum HR
Only a genuine maximal effort produces it, and cycling max typically sits 3–8 bpm below running max — keep the two sports separate.
3 min ~105% FTP · 2 min easy
3 min ~110% FTP · 2 min easy
3 min everything, 30 s seated sprint to close.
Peak lands 10–30 s into the last surge.
FTP
The 20-minute test is the common route, and the 0.95 correction is not optional — it is what turns a 20-minute number into an hour-power estimate.
FTP = mean power × 0.95
Retest every 4–6 weeks.
The reference standard
An incremental lactate test returns LT1 and LT2 directly; gas exchange returns VT1 and VT2, in both heart rate and watts. Every method on this page is a field approximation of what those two measure.