06-05-2016 08:12
06-05-2016 08:12
06-05-2016 08:50
06-05-2016 08:50
I'm afraid you can't at the moment. However, someone has created a feature request to add this and if you want to add your vote you can find it here:
https://community.fitbit.com/t5/Feature-Requests/Vibration-alerts-for-heart-rate-zones/idi-p/602519