Heart rate zones are a way of describing how hard you are working. They help you keep easy sessions easy and hard sessions hard. You do not need a lab test to use them.
The five zones
Most systems use five zones, based on a percentage of your maximum heart rate or threshold heart rate.
- Zone 1 — very easy. Warm-ups, recovery.
- Zone 2 — easy. Conversational. Builds aerobic base. See Zone 2 for hybrid racers.
- Zone 3 — moderate. Steady, harder to talk.
- Zone 4 — hard. Threshold. A few words only. See threshold runs.
- Zone 5 — very hard. Short, maximal efforts.
Setting your zones
Age-based formulas
Formulas like “220 minus your age” give a rough maximum heart rate, but they can be well off for individuals.
Field tests
A more accurate approach is a threshold test: a hard, steady 20 to 30 minute effort, using the average heart rate from the latter part as an estimate of threshold. Many watches and apps can set zones from this.
Talk test
The simplest method: if you can talk in full sentences, you are easy. A few words, you are hard.
Limitations
- Heart rate lags: it takes time to rise in short efforts.
- Outside factors: heat, caffeine, stress and poor sleep raise heart rate.
- Wrist monitors: less accurate in strength work and stations. Chest straps are more reliable.
In hybrid training
Heart rate is most useful for keeping easy runs easy. For stations and short intervals, effort and pace are often better guides. See training by RPE.