Support

Kiuas needs access to Apple Health. On your iPhone open Settings › Privacy & Security › Health › Kiuas and turn on at least Heart rate and Workouts, both to read and to write. The Watch app asks for the same permissions the first time you start a session there: allow them too.

Health doesn’t tell apps when reading is denied, so Kiuas can’t warn you: it just sees no data. If you said “Don’t allow” at first, the switches above are the only place to change it.

• Check that Kiuas is installed on the Watch: in the Watch app on your iPhone, under My Watch › Available Apps.
• Open Kiuas on the Watch once, keep the iPhone nearby with Bluetooth on, and both devices unlocked.
• You can always start the session directly on the Watch: your protocols are already there.

Without a Watch, choose Timer only on iPhone: same protocol, no heart rate and therefore no alerts.

The sensor has lost contact. Wear the Watch snug, a finger’s width above the wrist bone, and wipe away sweat or water. Until the signal is back there are no alerts, and the Watch says so instead of staying silent.

Yes. Every step is written to a journal on the Watch first. If the app closes, the session picks up where it was; if the Watch restarts, Kiuas saves what was recorded and marks the session as rebuilt so you can check it on the iPhone.

Apple estimates calories from your heart rate, with formulas made for exercise. In the sauna your heart rate rises by about 40 bpm, but your energy use barely does, so a heart-rate estimate comes out much higher.

Kiuas uses a model built on published studies of sauna and cold water and shows a range, not a single number. Your weight from Health and, if you enter them, the water temperature and how deep you went make the range narrower. The sources are listed in the app under How we estimate.

You choose, in Settings › Calories in Health: the Kiuas estimate (the default) or Apple’s. The change applies from your next session. Resting energy and heart rate are always recorded by your Watch as usual.

A caution is a heads-up: your heart rate went above your limit, or after the cold it isn’t coming down as expected. A haptic tap and a short message.

A stop means it’s better to finish: above your limit for minutes, or still high after five minutes of rest. It covers the screen and repeats until you answer. After you answer, the same alert stays muted for a few minutes.

By default it’s 85 % of your estimated maximum heart rate (208 − 0.7 × age), with your age from your date of birth in Health; without it, a cautious 160 bpm. Change it in Settings › Your limits, for example to the values your doctor gave you.

If you log alcohol or caffeine before starting, the limits are lowered for that session. If you take beta blockers or other medicines that lower your heart rate, turn on “I take medicine that lowers my heart rate”: Kiuas then uses a formula made for that (168 − 0.51 × age), and its alerts tell you.

They’re a help, not a diagnosis, and they can be late or wrong. Kiuas is not a medical device. If you have heart or blood pressure problems, are pregnant or take medication, ask your doctor before sauna and cold water. If you feel unwell, get out and ask for help.

Yes. Open the session in History and tap Correct: you can move the end, change a phase’s type or length, or remove a round. Kiuas replaces the workout in Health with the corrected version.

Settings › Data › Kcal by phase › Export CSV creates a CSV file with your last sessions saved from the Watch, phase by phase: duration, average heart rate, Apple’s and Kiuas’ calories, alerts. It opens the share sheet, so you can save it to Files or send it anywhere.

Your workouts are also in Apple Health, and can be exported from there with the Health app’s own export.

• One session: open it in History and tap Delete session. It’s removed from Kiuas and from Health.
• Everything in Kiuas: delete the app from your iPhone and from your Watch. Workouts already saved in Health stay there.
• Workouts in Health: in the Health app, go to Browse › Activity › Workouts › Show All Data and delete them there. A workout deleted only in Health stays in your Kiuas history; delete it in Kiuas too.
• Access to Health: revoke it at any time in Settings › Privacy & Security › Health › Kiuas.

Kiuas has no server and no account, so there’s nothing stored elsewhere to delete. Details in the privacy policy.

Your first 2 sessions are free, with every feature. From the third, starting a new session needs Kiuas Pro, monthly or yearly. There is no other free trial. Kiuas shows how many free sessions you have left above the start buttons.

The count is kept on your iPhone: deleting sessions or reinstalling the app doesn’t give them back.

On your iPhone, open Kiuas and go to Settings › Kiuas Pro, or tap Subscribe when Kiuas asks. The price is shown there, in your currency, before you confirm. Payment goes to your Apple Account. The full conditions are in the terms of use.

Sign in with the same Apple Account and open Settings › Kiuas Pro › Restore Purchases. Kiuas usually finds an active subscription by itself; Restore Purchases asks the App Store again.

In Kiuas, Settings › Kiuas Pro › Manage Subscription opens Apple’s subscription page. You can also go to Settings › [your name] › Subscriptions on your iPhone. Cancel at least 24 hours before the end of the current period to avoid the renewal. Kiuas Pro stays active until the end of the period you paid for.

Refunds are handled by Apple: request one at reportaproblem.apple.com.

Yes. If you share purchases with your family through Family Sharing, one Kiuas Pro subscription covers everyone in the group, each on their own devices.

You can’t buy on the Watch: subscribe on the iPhone. The Watch then picks up your subscription by itself, from the App Store and from your iPhone. If it still shows the message, open Kiuas on the iPhone with the Watch nearby, so the two can talk, then try again.

Everything except starting a new session after the free ones: your history, summaries, corrections, export, your workouts in Health, settings, and recovering a session that was left open. A session in progress never stops, even if your subscription ends during it.

No. Purchases go through Apple’s StoreKit and the App Store. Kiuas only learns whether a subscription is active, and never sees your name, email, Apple Account or card. Details in the privacy policy.

English, German, Italian and Finnish. It follows your iPhone’s language; you can pick another one for Kiuas alone in Settings › Kiuas › Language.

An iPhone with iOS 17 or later. For heart rate and safety alerts, an Apple Watch with watchOS 10 or later. Without a Watch, Kiuas works as a timer on the iPhone.