In watchOS 4, for some reason, breathe notifications use a series of witchcraft and undocumented mysteriousness to maybe sometimes eventually send you notifications.
I’ve found this to never be the case and be quite awful in practice. In that, I never freaking get notified.
My solution, until September, is to make a notification setting in the Streaks app.
Streaks is this awesome app that can remind you do a bunch of things, and keep up 'streaks'. What's awesome is Streaks integrates directly with HealthKit. Which means, if you do whatever item you want to accomplish (say, 5 breathing minutes), Streaks will notify you and automatically mark the task as complete!
So basically, it's a great habit maker without all the glitchiness of notifications of
hummingbird DeepBreathing on watchOS 4.
The first setting is simple enough - make a streak that encourages me to do at least 5 breathing sessions every day.
Second, you can edit the specific notification times by going into the top bar, taping the sideways … ellipsis, and then scrolling down. By default it only notifies you around the end of the day if you haven't done the task you've set out to do.
Lastly, I have custom times set so that I remember throughout the day, rather than at the end of the day, so I remember to Breathe.
Anyways, here's my setup. I honestly really like the breathing stuff in watchOS, but get frustrated when it just doesn't work.