The five heart rate zones
- Zone 1 (50–60%): very easy. Warm-ups, cool-downs and recovery.
- Zone 2 (60–70%): easy, you can talk in full sentences. Builds endurance and burns fat; most training time belongs here.
- Zone 3 (70–80%): moderate, talking gets harder. Improves aerobic fitness.
- Zone 4 (80–90%): hard, a few words at a time. Raises the pace you can hold.
- Zone 5 (90–100%): maximum effort for short intervals.
The formulas
Zone heart rate = maximum × percentage
Karvonen: resting + (maximum − resting) × percentage
Example
At 35, the maximum is 220 − 35 = 185. Zone 2 is 60–70% of that: 111–130 beats a minute. With a resting heart rate of 60, Karvonen gives 60 + 125 × 0.6 to 60 + 125 × 0.7: 135–148.
Frequently asked questions
How do I find my resting heart rate?
Count your pulse for 60 seconds just after you wake up, before getting out of bed, or read it from a watch or fitness tracker. Do it on a few mornings and take the average. If you leave it blank, zones are worked out from your maximum heart rate alone.
Which maximum heart rate formula is best?
Both are estimates. 220 − age is the classic one; the Tanaka formula (208 − 0.7 × age) is a little more accurate for older adults. If you know your real maximum from a hard test, enter it instead.
Why does adding my resting heart rate change the zones?
With a resting heart rate the calculator uses the Karvonen method, which works from your heart rate reserve (maximum minus resting). Fitter people with a low resting heart rate get zones that fit them better.
Is it safe to train in zone 5?
Zone 5 is all-out effort that you can only hold for short bursts. Build up to it, and talk to a doctor before hard exercise if you have a heart condition, are new to exercise, or take medicines that affect heart rate.
