Hi @momo0908 . Thanks for reaching out, and welcome to WHOOP! This can happen if the sensor sees wrist movement that resembles low-intensity activity, sometimes occurring from things like a loose strap and small motion patterns while you’re sitting.
A few quick steps usually clear this up:
1. Make sure the strap fit is snug
WHOOP reads HR best when worn about one finger-width above the wrist bone with no visible green light escaping. A slightly loose fit can cause motion artifacts that look like activity.
2. Reboot your device
To reboot your device, please navigate to Device Settings by selecting the device icon in your app. Then go to Advanced > Reboot Device.
3. Double-check that your app and firmware are fully up to date
Outdated versions can occasionally lead to inaccurate auto-detection.
If the issue persists, please reach out to support@whoop.com and our dedicated team can help.