u/EverydayGary

Disclosure: I built this. SnowFire — cold plunge / sauna / steam tracker for iOS + Watch. Trying to figure out if I should expand the breathwork side.

I do cold and sauna daily at my gym. Tried the existing tracking apps, all bad. So I built my own over the last few months. A couple weeks in I realized the most consistent ritual for me wasn't the cold timer — it was the 60 seconds of slow breathing right before I stepped into the tub. Without it I'd gasp out at 30 seconds. With it, I held breath control through the whole 3-minute exposure.

So I built breathing into the app. Four techniques visible in the picker today:

• Box Breathing (4-4-4-4 — Navy SEAL standby, with an animated square that traces corner-by-corner in sync with the cadence)
• Wim Hof (deep cycles + retention tracking)
• Physiological Sigh (Balban et al. 2023, Cell Reports Medicine — fastest research-backed stress reset)
• Cold Plunge Prep (slow controlled breath that reduces the cold-shock gasp reflex — Tipton 2014, J Physiol)

You can run them standalone OR stack them into routines that chain breath → cold → sauna → cold. The Box Breathing animation in particular has been the one my gym friends keep showing other people.

What's NOT there yet:

• Standalone breathwork sessions without thermal therapy attached
• Per-technique session history / streak tracking
• Benefit tracking for breath-only practices (HRV impact, vagal tone, etc.)

Right now breath lives mostly inside the cold/sauna workflow. I'm starting to think breathwork is its own surface that deserves session tracking + benefit tagging the same way the thermal side has it (we track 27 thermal benefits with magnitudes + evidence tags — norepinephrine up to 530%, BDNF up to 66%, cardiovascular risk down 63%, etc.).

So the question for this sub:

1. Is breath-only session tracking with HRV / RMSSD / vagal-tone benefit reporting actually useful, or do most of you just count cycles in your head and call it good?
2. Is there a technique you keep coming back to that I should add? I'd rather build the 5th technique someone actually wants than a generic 20th.
3. Would HealthKit integration (write breath sessions to Apple Health, pull HRV before/after) move the needle, or is that overengineering for a meditative practice?

Site: https://getsnowfire.app App Store: https://apps.apple.com/app/id6758926219

Open to feature requests — especially correlation analysis ideas if anyone's done their own personal experiment with cold/HRV or sauna/sleep.

SnowFire — thermal therapy tracker (cold plunge / sauna / steam) Disclosure: I built it. Used it daily at my gym for 2-3 months before launching it. Solo dev.

Built this because I was tracking sauna and cold plunge sessions in a spreadsheet and wanted real time-series data tied to specific protocols and benefit endpoints. iOS + independent Apple Watch app.

What I track per session:

• Therapy type (cold / sauna / steam / contrast)
• Temperature (auto-detected on compatible Apple Watches for cold plunge)
• Duration
• Heart rate samples (passive, from Apple Watch — no manual entry)
• Active energy burned
• Protocol adherence — which named protocol this session was part of (Søberg, Huberman, Patrick, etc.)

Aggregates:

• Weekly compliance per protocol (e.g. Søberg requires 11 min cold + 57 min heat across 4 sessions — am I hitting it?)
• Streak (current + longest)
• Session-type breakdown
• HR distribution per session type

Benefit endpoints I track (27 total, with magnitudes):

• Norepinephrine — up to 530% (Šrámek 2000, strong evidence)
• Dopamine — up to 250% (strong)
• Growth Hormone — up to 16× (Leppäluoto 1986, moderate)
• Brown Fat activation — ~188 kcal/day (strong)
• Cardiovascular — up to 63% cardiac death reduction (Laukkanen 2015 KIHD, strong)
• BDNF — up to 66% (moderate)
• Heat Shock Proteins — activated at core temp 38°C+ (moderate)
• 20 more across neurochemical / metabolic / cardiovascular / cellular / mental / physical / respiratory categories Every benefit is tagged with evidence level: strong / moderate / expert consensus / preliminary. So you can see what's an RCT-backed claim vs. expert synthesis vs. emerging research.

Protocol library (9 named, all with research citations): Søberg (Cell Reports Medicine 2021), Huberman (Huberman Lab 2022), Patrick / Rhonda Patrick (Laukkanen 2015), Growth Hormone (Leppäluoto 1986), Mood Enhancement (Janssen 2016 JAMA Psychiatry), Athletic Recovery (Piñero 2024), Sports Contrast, Nordic, SnowFire Advanced.

Where the data lives:

• HealthKit workouts (HKWorkoutActivityType.other) — visible in Fitness app, exportable via Health Auto Export, Bearable, etc.
• SwiftData with CloudKit private DB sync (iPhone, iPad, Watch)
• No external server. No analytics on session data. What it doesn't do (yet):
• No Garmin import — actively in development, should ship in the next couple weeks
• No CSV export inside the app (HealthKit → Health Auto Export → CSV workaround)
• No cross-metric correlation (cold vs. HRV, sauna vs. sleep) — would love feedback on what people would actually want here

Site: https://getsnowfire.app App Store: https://apps.apple.com/app/id6758926219

Open to feature requests — especially correlation analysis ideas if anyone's done their own personal experiment with cold/HRV or sauna/sleep.

I cold plunge at my gym every morning, paired with sauna and steam. Tried the existing tracking apps — won't name them but the ones you've heard of. None of them got the basics right. Sequential timers were broken. No way to save my routine (5 min cold → 30 min sauna → 1 min cold → 10 min steam). No real Apple Watch app. No protocol presets.

So I built one for myself. Used it at the gym every day for 2-3 months while I built it on the side. Each session at the gym was a feature request from me to me. Launched it a month ago.

Protocols

9 named research-backed protocols with weekly compliance tracking:

• Huberman — 11 min/wk minimum effective dose in 50-60°F water, 2-4 sessions (Huberman Lab May 2022)
• Søberg — 11/57 split, end on cold, natural rewarming (Cell Reports Medicine 2021)
• Patrick (Rhonda Patrick) — 4×/wk sauna at 174-180°F (Laukkanen 2015 — 63% cardiac death reduction in the Finnish data)
• Mood Enhancement — consistent short cold under 20°C (Janssen 2016 JAMA Psychiatry)
• Athletic Recovery — post-cardio cold, AVOID within 4hr of strength training (Piñero 2024 meta-analysis)
• Growth Hormone — 2× sauna with cooldown break (Leppäluoto 1986)
• Sports Contrast — 4:1 hot:cold cycles, 4×/week
• Nordic — traditional 3-round sauna/cold cycling
• SnowFire Advanced — full-spectrum

Benefit tracking that I genuinely look at: 27 endpoints with magnitudes and evidence tags. Norepinephrine up to 530% (Šrámek 2000), dopamine 250%, BDNF +66%, mortality risk −63% in the Laukkanen data, brown fat ~188 kcal/day. Every claim is tagged strong / moderate / expert consensus / preliminary so you can see what's RCT-backed vs. inferred from expert synthesis. That tagging was the whole point — no horoscope vibes.

The Apple Watch app ended up being my favorite part. Start a session from the wrist — quick session, your saved routine, or one of the protocol presets. HR through the entire session. Estimated kcal. On compatible watches it auto-detects and sets the cold plunge water temp. Leave the phone in the locker.

Made for iOS + Apple Watch.

Site: https://getsnowfire.app App Store: https://apps.apple.com/app/id6758926219