Should I train by power, heart rate or pace?

Use power where you have it, pace for flat running, and heart rate as the check that the other two are not lying — a heart rate well above the zone at the usual power is the body saying it is tired, hot or ill.

How often should I update my zones?

Whenever the threshold behind them moves — after a new FTP test, a new race or a new lactate test, typically every six to ten weeks in a build. LaChart updates every zone table when a test is saved.

Why are my heart-rate zones different from a percent-of-max formula?

Because maximum heart rate says little about where your threshold sits. Two athletes with the same maximum can have LTHR 15 beats apart; zones anchored to the threshold follow the athlete, zones anchored to the maximum follow the formula.

Free tools · no account needed

Training Zones Calculator

Power, heart rate and run pace zones from your threshold values

Training zones

Power, heart rate and run pace zones from your threshold values.

Fill in at least one field. All zones use your threshold values.

FTP (W) — power zones

LTHR (bpm) — HR zones

Threshold pace (mm:ss/km)

How the training zones calculator works

Training zones are bands of intensity with a purpose each, anchored to a threshold. Power zones use FTP and the seven-zone Coggan model; heart-rate zones use your lactate threshold heart rate (LTHR) with five bands; run pace zones use your threshold pace. Enter whichever thresholds you have and the calculator builds every table it can.

Power responds instantly and is the most precise; heart rate lags a minute or two and drifts with heat, fatigue and caffeine, but it is the one you have on every run and swim; pace is the truth for running on flat ground. The three tables describe the same physiology from three sides, which is why LaChart shows them together.

Zones from a single threshold assume the shape of your curve below it. A lactate test measures that shape: LT1 becomes the top of Zone 2 and LT2 the top of Zone 4, and the zones are yours rather than an average athlete's.

Questions

Should I train by power, heart rate or pace?: Use power where you have it, pace for flat running, and heart rate as the check that the other two are not lying — a heart rate well above the zone at the usual power is the body saying it is tired, hot or ill.
How often should I update my zones?: Whenever the threshold behind them moves — after a new FTP test, a new race or a new lactate test, typically every six to ten weeks in a build. LaChart updates every zone table when a test is saved.
Why are my heart-rate zones different from a percent-of-max formula?: Because maximum heart rate says little about where your threshold sits. Two athletes with the same maximum can have LTHR 15 beats apart; zones anchored to the threshold follow the athlete, zones anchored to the maximum follow the formula.

Lactate analysis

LT1, LT2, OBLA from blood lactate step tests

Progress tracking

Fitness trends across weeks and months

Training zones

Power, HR and pace zones for every sport

Coach tools

Several athletes, shared test reports

Ready to track your full training load?

LaChart combines lactate testing, training analytics, Strava and Garmin sync and coach collaboration in one place.