Read the definition before the number
One plan may define zones from physiological thresholds measured during testing. An app may estimate them from a percentage of maximum heart rate. Another may use heart-rate reserve, which also incorporates resting heart rate. Matching labels do not establish matching boundaries.
That is why copying someone else's beats-per-minute range can be misleading, even when both devices display “Zone 2.”
Three details worth finding
- Which variable defines the zone: heart rate, power, pace, or another measure?
- How were the boundaries determined: measured testing, a personal performance, or a population formula?
- What is the session intended to feel like and accomplish?
A zone based on an estimated maximum heart rate inherits uncertainty from that estimate. A medication that affects heart rate can also make generic targets inappropriate.
You do not need a perfect zone to move usefully
Broad activity guidance uses intensity categories rather than requiring a particular app's color band. For many everyday sessions, perceived effort and the ability to talk provide useful context alongside the device. If the watch and your experience disagree, investigate the settings and conditions before treating the colored number as a verdict on whether the exercise counted.
