It is possible to customize the heart rate zones if you have previously had a metabolic assessment by tapping on HEART RATE INFO under the MORE tab.
For convenience, by default, the heart rate zones are simply divided based on your MAX heart rate.
Here is an example on how the default zones are calculated for a MAX heart rate of 200 bpm.
|Zone Name||HR Percentage||If MAX HR = 200|
|RED LINE||>90%||180 and above|
|HARDCORE||80 - 89%||160 - 179|
|ENDURANCE||70 - 79%||140 - 159|
|FITNESS||60 - 69%||120 - 130|
|WARMUP||< 59%||119 and below|