During a workout, your screen is OFF by default to save battery. If you want to turn it on, please perform the following steps:
- Open the Withings App.
- Tap Devices and look for your ScanWatch.
- Tap All settings.
- In Workout, activate Keep display ON.
https://support.withings.com/hc/en-us/sections/4411036796433-ScanWatch
https://support.withings.com/hc/en-us/sections/360002127637-Tutorials