What training zones are for

Training zones translate an internal or external intensity marker into practical ranges. They help separate recovery, easy endurance, steady work, threshold training and high-intensity sessions. The goal is not to stare at one number every second; it is to keep the purpose of each session clear.

This calculator includes three independent methods. Heart-rate zones use heart-rate reserve, running pace zones use threshold speed, and cycling zones use functional threshold power. Do not compare the zone numbers across methods as if they were interchangeable. Heart rate responds to strain, pace reflects movement speed and power measures work rate.

Heart-rate reserve zones

The heart-rate reserve method accounts for both resting heart rate and maximum heart rate. The calculator subtracts resting heart rate from maximum heart rate, applies each percentage, then adds resting heart rate back. This is often more individual than using a simple percentage of maximum heart rate alone.

• Measure resting heart rate when calm and well recovered.
• Use an observed maximum when available; age formulas can be inaccurate for individuals.
• Expect heat, dehydration, altitude, fatigue, caffeine and stress to change heart rate at the same pace.
• Allow heart rate time to respond during short intervals instead of chasing the watch immediately.

Running pace zones from threshold pace

Threshold pace is approximately the fastest pace you can sustain for a prolonged hard effort under stable conditions. The calculator converts threshold pace into speed, applies percentage bands, then converts those bands back to pace. Because pace and speed are inverse, a higher percentage of threshold speed produces a lower minutes-per-kilometre number.

Use a current threshold estimate from a suitable field test, race or established training data. If your input is too aggressive, every zone becomes too fast and easy days stop being easy. Terrain and weather also matter: on hills or in extreme heat, effort and breathing may be more useful than forcing the flat-course pace range.

Cycling power zones from FTP

The cycling calculation uses the familiar seven-zone percentage model around functional threshold power. Power reacts instantly and is not directly affected by wind or gradient, which makes it useful for structuring intervals. FTP is still an estimate, however, and different test protocols can produce different values.

Retest when training data consistently shows that the zones no longer match the intended effort. Avoid changing FTP after every good or bad session; zones should be stable enough to guide a training block.

How to use zones without becoming a slave to them

Think of each range as a guardrail. Easy and endurance sessions should feel controlled enough to support consistency. Threshold work should be hard but repeatable for the prescribed duration. High-intensity work depends on interval length, recovery and the objective of the workout.

Use more than one signal. Pair the zone with breathing, perceived exertion, terrain, temperature and how well you are recovering. Cardiac drift on a long run, for example, can raise heart rate while pace stays constant. That does not automatically mean the session failed; it is information about strain.

Frequently asked questions

Which method is best for running?

Pace is useful on flat, stable terrain, while heart rate adds context about physiological strain. Many runners use both alongside perceived effort.

Why do my Garmin zones differ?

Your device may use a different model, threshold value, sport profile or number of zones. Check its method before comparing numbers.

How often should I recalculate?

Recalculate after a meaningful fitness change or a reliable retest, not after every workout. Resting heart rate may be monitored more frequently, but temporary changes do not always justify new zones.

Are Zone 2 numbers universal?

No. “Zone 2” depends on the system being used. Always state the method, not just the zone number.

These zones are educational estimates, not medical thresholds or a personalised training prescription.