Where do I get my threshold heart rate?

From a test: run 30 minutes alone as fast as you can and take the average heart rate of the final 20 minutes. Estimating from age is considerably less accurate.

Do the same zones apply on the bike?

No. Cycling heart rate typically sits several beats lower than running. If you do both seriously, you need two sets of zones.

My heart rate does not match how I feel — why?

Heat, poor sleep, stress and illness all shift heart rate. On days like that your own perception is the better guide.

Training Zones

Lactate threshold HR

Z1 Recovery: < 145 bpm

Z2 Aerobic: 145-153 bpm

Z3 Tempo: 155-162 bpm

Z4 Threshold: 163-173 bpm

Z5 VO2: > 173 bpm

Why training zones?

Not every session should feel the same. Zones split effort into bands — from very easy to maximal — so you know where you currently are.

This calculator derives your zones from threshold heart rate: the pulse you can hold at your limit for roughly an hour. Ideally it comes from a test rather than an estimate.

How it is calculated

All five zones are percentages of lactate threshold heart rate (LTHR): Z1 below 85 %, Z2 85 to 90 %, Z3 91 to 95 %, Z4 96 to 102 %, Z5 above 102 %.

Threshold is the anchor because you can measure it yourself with a 30-minute test and it moves as you train — maximum heart rate does neither.

Example: LTHR 170. Z2 = 170 × 0.85 to 170 × 0.90 = 145 to 153. Z4 = 170 × 0.96 to 170 × 1.02 = 163 to 173 beats per minute.

The boundaries follow Joe Friel's running zones; on the bike the percentages sit slightly lower, because heart rate is lower for the same effort.

To calculate your training zones, take the threshold as the average heart rate of the last 20 minutes of a 30-minute solo time trial.

The most common mistake

Most recreational athletes train too often in the middle — too hard to recover, too easy to stimulate. Easy sessions should genuinely feel easy.

Zones are personal. Your numbers say nothing about anyone else's, even at the same age.

Frequently asked questions

Where do I get my threshold heart rate?: From a test: run 30 minutes alone as fast as you can and take the average heart rate of the final 20 minutes. Estimating from age is considerably less accurate.
Do the same zones apply on the bike?: No. Cycling heart rate typically sits several beats lower than running. If you do both seriously, you need two sets of zones.
My heart rate does not match how I feel — why?: Heat, poor sleep, stress and illness all shift heart rate. On days like that your own perception is the better guide.