SENSOR CONTEXT
Cadence lock and heart-rate spikes: how to check your running data
A surprising heart-rate trace can affect several downstream metrics. First check the recording; avoid assigning a physiological explanation from its shape alone.
Begin with measurement context
Identify the device and measurement source. An optical wrist reading, a chest-sensor stream and a manually entered average are not identical recording methods. Apple explains that Watch heart-rate readings can contain anomalies and may not always be reliable for every person.
Check the timestamp of the unusual section, whether data are missing around it and whether the pattern appears in the original provider view. You are looking for recording context before interpreting a score derived from that recording.
Could this be cadence lock?
Cadence lock is an optical-sensor error in which movement related to your steps is mistaken for your pulse. Garmin describes this failure mode in its accuracy guidance. A trace near 170 bpm alongside 170 steps per minute is a reason to inspect the original recording and sensor fit, not proof of an error. Do not delete high readings merely because they resemble cadence.
These invented patterns illustrate review questions rather than diagnosing sensor faults.
| Observed pattern | Useful next check |
|---|---|
| An abrupt step from 145 to 180 bpm | Inspect adjacent samples, workout structure and the original source |
| A long, perfectly flat section | Check sample timestamps and whether the display filled missing data |
| A blank middle section | Check coverage before using a whole-run average |
| A similar-looking HR and cadence trace | Compare units and source data; similarity alone does not establish artifact |
A chart can motivate an investigation, but its shape alone cannot establish that a value is false or explain a person's physical state.
Check what changed in the derived metrics
For an illustrative run at 3 m/s, pairing speed with 150 bpm gives a heart-rate cost of 50.0. Pairing the same speed with 180 bpm gives 60.0. The ratio changes by 20% because its heart-rate input changed. That arithmetic does not determine which reading was correct.
Before correcting or excluding values, preserve the original activity. Record the basis for any edit and avoid removing only the readings that make the result less flattering. If the cause remains unclear, retain the uncertainty in your comparison.
Use the remaining evidence appropriately
In Runome, inspect available activity charts and source information. An uncertain heart-rate section may limit efficiency or zone interpretation while still leaving useful distance and time data. Do not treat a smooth reconstructed curve as evidence that a missing measurement was recovered.
The coverage example shows how gaps affect an average. Pulse points versus continuous streams explains another important distinction. These are data-review steps, not a way to diagnose symptoms or rule out a health concern.