Built around rounds

  • Round-by-round timer, with breaks and cool-downs timed separately.
  • Live Activity and Dynamic Island: round, timer and temperature on the Lock Screen, without unlocking.
  • Control Center: start a session in one tap, without opening the app.
  • Minimize the session to the tab bar and keep using the app.

A log that knows what a sauna is

Each session keeps the temperature, humidity and sauna type, your mood and stress before and after, and what you did around the heat: cold plunge, sauna hat, face ice and water.

A score out of 100

Heat, rounds, cool-down and hydration all count. Every session gets a score that shows what made it a good one. The body estimates add sweat lost, calories, what to drink and your sodium, potassium and magnesium losses.

How long, how hot, how often

Not sure where to start? How often, how long, how hot sums up the rhythm most studies use, and Drink what you sweat covers what a session costs in water.

Free to download

The timer, the journal, the score, your heat age, widgets and badges are free. Sauna Metrics Pro adds the Apple Watch app, the Health analyses, the training log and the full recaps, with a free week to try. No account and no ads.

Find your sessions in your sauna log

Keep temperature, humidity, sauna type and notes together. Return to your session history to compare your routine over time.

Keep heat and cooling in context

Time sauna rounds and breaks separately. You can note a cold plunge as part of a sauna session; this is not a dedicated ice bath timer or a measurement of water temperature.

Compare the Health data you have

With your permission, compare available heart rate, HRV and sleep data. Missing measurements stay missing, and comparisons do not establish that sauna caused a change.

Questions

Is Sauna Metrics free?

The download is free, with the timer, the journal, the score, your heat age, widgets and badges. Sauna Metrics Pro adds the Apple Watch app, the Health analyses, the training log and the recaps, with a free week to try.

Do I need an account?

No. There is no account, no ads and no tracking: your data stays on your iPhone.

Does it work with Apple Health?

Yes. With your permission, the app reads heart rate, resting heart rate, HRV, sleep, active energy, weight and blood pressure on the device, and can save your sessions to Health as workouts.