Heart Rate Zone Calculator

What Are Heart Rate Training Zones?

Heart rate training zones are ranges of heart rate — expressed as beats per minute (bpm) or as a percentage of your maximum heart rate — that correspond to different physiological states and training adaptations. Training in different zones produces different fitness outcomes: Zone 1 and 2 training builds aerobic base and improves fat metabolism; Zone 3 and 4 training improves lactate threshold and race pace; Zone 5 training maximises cardiovascular capacity and speed.

Using heart rate zones allows you to train with purpose rather than feel — ensuring your easy runs are truly easy (most people run their easy days too fast), and your hard sessions are hard enough to produce the intended adaptation.

The Karvonen Method vs Simple Percentage

The simple method calculates zones as a percentage of maximum heart rate only (e.g. Zone 2 = 60–70% of max HR). The Karvonen method (Heart Rate Reserve method) factors in your resting heart rate, which makes zones more personalised to your individual cardiovascular fitness level. Research supports the Karvonen method as more accurate for predicting actual exercise intensity and training outcomes.

How to Accurately Measure Your Resting Heart Rate

Accurate resting heart rate (RHR) measurement is essential for the Karvonen method. Measure it first thing in the morning before getting out of bed — ideally after waking naturally without an alarm. Count your pulse at your wrist or neck for a full 60 seconds. Average over 3 consecutive mornings for the most reliable reading. Normal RHR is 60–100 bpm; well-trained athletes are often 40–60 bpm.

Frequently Asked Questions

References

1. Karvonen MJ et al. The effects of training on heart rate. Ann Med Exp Biol Fenn. 1957;35(3):307-315.
2. Tanaka H et al. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156.
3. Seiler S, Tønnessen E. Intervals, thresholds, and long slow distance. Sportscience. 2009;13:32-53.