Cold Metric is now on the store. Ice bath, sauna, cold shower and breathwork, with contrast sets as the main event.
The constraint that shaped the whole thing: you can't see or hear a watch with your wrist under water. So there's nothing to read during a session. Every transition is a haptic pattern distinct enough to identify by feel — halfway, ten seconds out, round over, session over. Tested in an actual ice bath rather than assumed; the vibration motor and the button both work fine submerged.
A few decisions other devs might find relevant:
- Contrast rounds are laps, so Connect shows the whole cycle rather than one undifferentiated block.
- It files as Cardio Training rather than generic, so sessions don't land in Connect as "Other" — which is the recurring complaint in the cold plunge threads on here. Breathwork uses Meditation / Breathing instead.
- Water temperature and cold time are written as FitContributor session fields.
- Between rounds the clock stops and waits for a button press. Getting out of a barrel and into a sauna takes as long as it takes, and counting that as sauna time makes the round a lie.
28 devices: fenix 8 and 9, epix Pro, Venu 3/4/X1, Forerunner 955/965/970, MARQ 2, Enduro 3, vivoactive 5 and 6, tactix 7/8, D2.
apps.garmin.com/.../805c0f49-e594-4df3-8993-652db7870251 — paid, one purchase, no subscription.