How do I control the sound of reminders?
On iOS, to turn them off, go into your iPhone settings and choose Notification Center and then scroll down and choose Coach.me. You'll see an option under that for Sounds; just turn that off and you'll be all set.
On Android: we recently added audible reminders after receiving many requests for them from users. However, we don't yet have an option for turning off the audible portion of reminders. We'll be adding that in a future release. In the meantime, you'd need to turn off push notifications to turn the sound (and the push reminder in general) off. To do that, tap on your profile photo at top right; choose Reminders from the drop down.