Heart rate zones are ranges of pulse used to dose training intensity. They are calculated as a percentage of the maximum heart rate or of the heart rate reserve.
Training in different zones develops different qualities — from recovery to maximum power.
Why zones are needed
Working in the right zone helps you train purposefully: too light a load has no effect, too heavy a one causes overexertion. According to AHA guidelines, moderate activity corresponds to about 50–70% of the maximum, vigorous to 70–85%. It is useful to do most of your base aerobic work in zones 2–3.
How to calculate your zones
First estimate your maximum heart rate (for example, 208 − 0.7 × age), then take the percentages for each zone. A more accurate way is to calculate from the heart rate reserve using the Karvonen method, taking the resting pulse into account. The pulse is convenient to monitor with a chest strap or a watch.
Reference ranges
The five heart rate zones as a percentage of maximum heart rate:
| Zone 1 — recovery | 50–60% |
| Zone 2 — aerobic base, fat burning | 60–70% |
| Zone 3 — aerobic endurance | 70–80% |
| Zone 4 — anaerobic threshold | 80–90% |
| Zone 5 — maximal | 90–100% |
Calculate using this marker
Calculators where Heart-rate zones is used directly:
Frequently asked questions
In which heart rate zone is fat burned?
The most fat is used as fuel in zone 2 (about 60–70% of maximum). But for weight loss, the total energy expenditure matters more than the 'fat-burning' zone alone.
How much should you train in each zone?
For health and endurance, most time is spent in the light zones 1–2, adding short segments in zones 4–5. This approach reduces the risk of overtraining.