HIIT workouts

There are a few workouts on the watch under “cardio” or you can download some or create a custom workout from the Garmin Connect app by going to (iPhone) “more”, “training”, “workouts”, “find a workout” or “create your own”.  You can save it and sync it to your watch.  Most of the “workouts” should sync to your watch under the “cardio” workout.

Does HIIT works with your VENUSQ? I created a Workout but when I want to transfer it to the watch t say to me that is not compatible

Because the SQ doesn't have this 'HIIT' feature. You can create the workout under Strength or Cardio.