Beatcast
Heart rate zones explained
By Andreas B. Diendorfer · ORCID · LinkedIn · Updated
Short answer
A heart rate zone is a range with a name. You draw the ranges from an anchor: a share of your maximum, a share of your heart rate reserve, or a share of your threshold. Which anchor fits depends on what you know about yourself. The names differ between apps because the names are a convention.
Last checked: 12 October 2026.
Three anchors
Percent of maximum. Each zone starts at a share of your maximum heart rate. Beatcast's five zones start at 50, 60, 70, 80 and 90 percent. If you don't have a measured maximum, an estimate from age is the usual stand-in. Beatcast uses Tanaka: 208 minus 0.7 times age. Try the max heart rate calculator.
Heart rate reserve, or Karvonen. The same shares applied to the gap between resting and maximum, then added to your resting rate. It adapts to a fit person with a low resting rate. It needs a resting number you trust. See the Karvonen calculator.
Percent of threshold. If you know your lactate threshold heart rate, zones are shares of it. Beatcast's five zones start at 65, 85, 90, 95 and 100 percent of it. A threshold from a proper test is better than any age formula, and harder to get.
Which one to pick
Percent of maximum is the simplest. Karvonen suits you if you know your resting rate. Threshold suits you if you have been tested. None is right for everyone. Treat the result as a starting line and adjust it.
The default five zones
At 180 maximum:
| Zone | Name in Beatcast | Starts at | Share of max |
|---|---|---|---|
| 1 | Recovery | 90 | 50% |
| 2 | Endurance | 108 | 60% |
| 3 | Tempo | 126 | 70% |
| 4 | Threshold | 144 | 80% |
| 5 | Max | 162 | 90% |
A zone runs from its lower number up to, but not including, the next one. The top zone has no ceiling.
Fewer zones
Three zones start at 60, 70 and 85 percent of maximum, and are called Easy, Steady and Hard. Two zones start at 60 and 85, called Easy and Hard. The two-zone line sits where the three-zone scheme says hard, so switching between them doesn't move the line that matters. Beatcast lets you rename any of them.
Why names differ
Garmin, Polar, Apple and the rest each name and cut zones their own way. Polar's are Very Light, Light, Moderate, Hard and Maximum. Garmin's default names are Warm Up, Easy, Aerobic, Threshold and Maximum. There is no standard. When a coach says zone 2, ask which scheme. The zone 2 calculator shows four of them side by side.
An estimate is an estimate
An age-based maximum can be roughly a dozen beats off for one person (Nes and colleagues reported a standard error of 10.8 in 2013). These are training estimates. If you take medication that changes your heart rate or have a heart condition, ask your clinician before using age-based numbers.
Where Beatcast fits
Beatcast builds zones from these anchors, tints the readout in your zone's colour, and keeps the number on the Lock Screen. Onboarding asks for your age and builds a start. A sensor is required. Beatcast on the App Store. Fourteen days free, then one purchase.
Questions
What is zone 2?
In Beatcast, 60 to 70 percent of maximum, called Endurance. Other schemes differ.
Can I set my own boundaries?
Yes, by hand.
Which formula should I use for max?
Beatcast starts from Tanaka and takes a measured number if you have one.
Where is the calculator?
The zones calculator. For energy at a given heart rate, there is a calories burned by heart rate calculator.
Good to know
Beatcast is not a medical device. It is built for training and general wellbeing, and it cannot detect, diagnose, treat or monitor any condition. If something about your heart worries you, talk to a doctor rather than to an app.
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