What do the heart rate zones mean?
- Zone 1 – Recovery: very easy. For warm-ups, cool-downs and recovery runs after hard days.
- Zone 2 – Endurance: this is where endurance is built. You can still talk comfortably. Most of your training – often quoted as about 80% – should be in zones 1 and 2.
- Zone 3 – Tempo: brisk but controlled. Typical for longer tempo runs and marathon race pace.
- Zone 4 – Threshold: “comfortably hard” – roughly the effort you could hold for about an hour in a race. You can only speak in short sentences.
- Zone 5 – Maximum: short, very hard efforts such as intervals or a finishing kick. Only possible for a few minutes at a time.
How the calculator works
Without further input, the calculator estimates your maximum heart rate from your age with the formula 208 − 0.7 × age (Tanaka et al., 2001). It is considered more accurate than the well-known rule of thumb 220 − age, but can still be off by 10 beats or more for an individual. If you know your real maximum, enter it – your zones will be much more accurate.
If you also enter your resting heart rate, the calculator uses the Karvonen method: the percentages then refer to your heart rate reserve, the gap between resting and maximum heart rate. Well-trained runners with a low resting heart rate get better-fitting zones this way.
Heart rate or pace?
Heart rate shows how hard your body is working – regardless of heat, wind or hills. On the other hand it lags behind and slowly drifts up on long runs. Many runners use heart rate for easy runs and pace for hard sessions. You'll find the matching pace for each zone in the training pace calculator.
Wrist-based heart rate monitors are often inaccurate during intervals; a chest strap is more reliable. If you have heart or circulation problems or take medication that affects your heart rate, have your training zones checked by a doctor.