Apple Watch & iPhone
Face the cold.
Track your progress.
Guided, measured. Get stronger week by week.
- Runs entirely on your iPhone
- Even better with Apple Watch
- No account needed
What the cold gives you
Into the cold. Stronger through the day.
Wide awake
Just a few minutes of cold raise norepinephrine and dopamine markedly — your body's own messengers for alertness and focus.
Mentally tough
Choosing to follow through: staying calm when everything in you wants to stop. You carry that resilience into your day.
And you feel it
Week by week you feel better — and your tracked progress is the proof.
How it works
01
Start a session
One tap on your iPhone or Watch. The lead-in gives you time to get under the shower — and the optional breathing exercise gets you ready.
02
Into the cold
The timer runs — cues and vibration guide you, with no glance at the display. Water protection keeps the session going until you end it yourself.
03
See your progress
Your routine takes hold, your body adapts. With Apple Watch you see all your heart-rate data in real time.
Even without an Apple Watch
Strong on iPhone. Stronger with the Watch.
What matters most runs on your iPhone. The Watch goes deeper.
iPhone only
Everything that matters included
- Guided timer with a lead-in and automatic stop
- Breathing exercise — guided by vibration or voice cues
- Every session with temperature and notes
+ Apple Watch
Real measurements on top
- Live heart rate for the whole session.
- Heart-rate trends over weeks — your progress in numbers
- Every session as a workout in Apple Health
Measurable
Colder, calmer, longer.
Your body adapts — and you can read it, not just feel it.
- How your heart rate calms and you handle the cold better — week by week.
- Trends for heart rate, temperature, duration, and recovery.
- Share your progress card — and spur others on.
Why cold?
What cold can really do.
From your body's own furnace to the clear head afterward — what the research actually shows.
+40%
better insulin sensitivity after 10 days of cold — measured in people with type 2 diabetes.
55 studies
show that a cold bath reduces muscle soreness after exercise — the best-documented effect.
12–15 °C
A clear effect already sets in here — no ice water needed, just "uncomfortably cold, but safe."
+530%
more norepinephrine in cold water — the messenger for alertness and focus, with no caffeine crash.
Every session in detail
Peak, average, recovery.
From the first cold shock to the recovery afterward — recorded beat by beat.
- Complete heart-rate curve with peak, average, and recovery.
- Type, temperature, and program day captured for each session.
- Your own notes on each session.
Step by step
From beginner to ice-bath pro.
Three programs guide you week by week — colder and longer, as soon as your body is ready.
- Cold Starter — 4 weeks, a gentle start from 30 seconds.
- Cold Seeker — 5 weeks for the more advanced.
- Cold Master — 5 weeks of ice baths, with rest days built in.
Optional before the cold
Breathe deep before you begin.
Get ready for the cold with a breathing exercise.
- Power Breathing, Box Breathing, and Calm Focus — from activating to calming.
- Guided by vibration — or, if you like, with spoken cues.
- Female or male, available in several languages.
Dashboard & overview
What you once forced becomes routine.
Your progress, your dashboard — at a glance.
- Large streak ring and weekly overview — your routine in numbers.
- You set your training and rest days — reminders only on training days, and rest days don't break your streak.
- Reorder cards, hide the streak, show notes — however it suits you.
Your measurements are yours.
Your Watch and iPhone sync directly with each other — only your cross-device backup goes to your personal iCloud. Turn iCloud off and everything stays local — your Watch and iPhone keep syncing anyway.
- No account
- Only your iCloud
- No data collected
Common questions
Good to know.
Do I need an Apple Watch?
No. Everything that matters — the timer, breathing exercise with voice cues, programs, temperature, streak, and history — runs on the iPhone alone. With an Apple Watch you also get live heart rate — and the countdown you can feel, which guides you without a glance at the display.
What happens if I decline access to Apple Health?
The app still works. Without Health access, the timer runs perfectly normally — you just don't get your Watch sessions saved automatically as a workout in Apple Health, or the live heart rate. You can grant access later at any time.
Is my data uploaded to the cloud?
Your Watch and iPhone exchange sessions directly with each other — no cloud needed. Yourpersonal iCloud receives only what we need for backup and syncing across the multiple devices on your iCloud account. That's Apple's end-to-end ecosystem; we run no servers of our own and can't see your data. If you're not signed in to iCloud, or you turn iCloud off for the app, everything stays local — your Watch and iPhone still keep syncing. Our app never uploads your heart-rate analyses to iCloud — they stay local in the app. (The raw data in Apple Health is managed by Apple itself, end-to-end encrypted.)
Does heart-rate measurement work underwater too?
The Apple Watch's optical sensor measures in water too. Cold skin can affect the signal slightly — a somewhat snugger band improves quality. The timer and all other features work independently of this.
Which cold sessions can I track?
Cold shower, cold plunge (ice barrel, tub), and open water (lake, sea, river). The cold shower is free; cold plunge and open water are part of Pro.
What does Cold Mastery cost?
The core is free and stays free: the cold shower, the guided timer with a breathing exercise (via vibration), streak and progress, and the Cold Starter program — plus, with an Apple Watch, live heart rate along with all the trends. Pro unlocks cold plunge & open water, the progression programs (Seeker & Master), the voice cues, and export — as a subscription or a one-time purchase (lifetime).
Is this a medical device?
No. Cold Mastery is a wellness and fitness tracker, not a medical device, and gives no medical advice. Cold exposure carries risks — when in doubt, ask your doctor before you start.
Free & Pro
The daily routine is free.
Cold showers, the timer, the breathing exercise, streak, and live heart rate cost nothing. Pro adds more session types and deeper analysis.
Free
The core, free forever
- Cold shower session type — no limit
- Timer, breathing exercise (via vibration), streak & level
- Cold Starter program to get going
- Live heart rate & all trends (with Apple Watch)
Pro
More options, more depth
- More session types: cold plunge & open water
- Progression programs: Cold Seeker & Cold Master
- Voice cues & more breathing patterns (Box, Calm)
- Data export (CSV)
Pre-launch
Be there when it gets cold.
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