When using a compatible Garmin watch, you can see not only your Stryd power number but also your Stryd Power Zone information while running. The zone information is calculated based on your Critical Power. This means that if your Critical Power changes, your power zones change as well.
You must use the Stryd Zones data field to see Power Zone information.
Numerical Zone: Stryd uses a 5-zone system. When enabling Numeric Zone, the Stryd data field will show the number of the zone on your watch (1 - 5) while running.
Visual Zone Bar: when setting up your watch, you must have one Garmin Data Screen dedicated to Stryd Zones (i.e. you cannot combine Stryd Zones with other data fields). The Visual Zone Bar will appear on the left of the Garmin screen and visually show your zone information.
Below are the instructions to enable both the Visual Zone Bar and Numeric Zone information. You can also use Garmin Express on your computer to configure Stryd Zones (similar procedure):
For newer watches, you need to access the Stryd Zone Settings via Garmin's ConnectIQ App