Spinning & Workout Mode
1) Go to your Fitbit and navigate to your device settings.
2) Select Exercise shortcuts
3) Select Spinning
4) Choose add to shortcuts
5) Sync your device.
After that, you should be able to find Spinning as an option under the exercise menu on your blaze.
You will also see the "Workout" option in Exercise shortcuts. You can re-add that also in addition to "Spinning."