The short version: CalmTide computes everything on your device. There is no account, no analytics, and no server that receives your health data. Nothing about your body, sleep, workouts, mood, or stress ever leaves your iPhone.
Last updated: 10/22/2026
What CalmTide reads
With your explicit permission, CalmTide reads data from Apple Health to compute your scores. Since version 1.8, a single Health sheet on first launch lists every type CalmTide can read, and you allow or skip each one: the core inputs — workouts and their energy, heart rate, heart-rate variability, resting heart rate, sleep analysis and mindful sessions — and the secondary ones — walking heart rate, respiratory rate, blood oxygen (SpO₂), VO₂ max, time in daylight, Apple stand time (time on your feet), environmental sound exposure, body mass and dietary caffeine. If you set CalmTide up before 1.8, an Insights card offers the secondary types once, in Apple's own sheet. No type has been added to what CalmTide declares since version 1.5.
Two read permissions are new in version 1.5, and each is optional and separately prompted:
- State of Mind (daily mood). Requested by its own contextual prompt at your first daily check-in, alongside the matching write described below. Granting read lets a mood you logged in the Health app — or in any other app — stand in for a CalmTide check-in you missed. Your own in-app entry always takes precedence.
- Dietary caffeine. Read-only, and used for the caffeine-timing insight and nothing else.
Declining any of these leaves the rest of the app working normally; CalmTide works with whatever you grant.
CalmTide reads this data to calculate your HPA Balance Score, daily load estimate, readiness and trends. All processing happens on your device. That includes the personalized benchmarks and the data-confidence indicator added in version 1.3; the overnight-HRV window, sleep-regularity scoring, sleep-continuity figures and social-jetlag calculation added in version 1.6; the morning-light coaching, circadian anchor score, and life-event annotations added in version 1.4; and, added in version 1.5, the weekly retrospective that ranks what moved your score, the morning-after patterns for caffeine, alcohol, late meals and hard sessions, the caffeine-timing insight, the check-in insights that compare your own check-in ratings across your own days, the practice hub's suggestions, your chosen goal focus, and your personal records. Each is computed on your device, from your own Health data, your own check-ins, and general published reference ranges — nothing about them is sent anywhere. Life events you pin to your trend, and the goal you choose to focus on, are stored only on your device.
The optional Calm Coach explainer also runs on your device — using Apple Foundation Models where the device supports them, and a deterministic fallback everywhere else — and is grounded only in your own metrics. Every line the on-device model writes is labelled as generated by an on-device language model. It is non-diagnostic, and no prompt, metric, or reply is sent to a server.
Apple Watch. Since version 1.8, the watch app reads your heart rate during a breathing session so it can show it live. To receive that live reading it starts a short mind-and-body workout session, which is discarded when the practice ends — no workout is ever saved to Health. Declining leaves the haptic-paced session working without a readout. Since version 2.0, for CalmTide Pro users who have finished setup, Apple Health can wake CalmTide in the background when new sleep analysis arrives, so the readiness complication is current when you wake. That background work reads nothing while your iPhone is locked, and the only thing it sends anywhere is the phone-to-watch update to your own paired Apple Watch.
What CalmTide writes
CalmTide writes exactly two sample types to Apple Health. Both are user-originated: each one records something you did in the app, and neither is ever created on your behalf.
- Mindful Sessions (Mindful Minutes) — added in version 1.4, unchanged since. When you complete an in-app breathwork or resonance-breathing session, CalmTide saves that session to Apple Health, with your explicit one-time permission, so your practice appears in the Health app and counts toward CalmTide's mindfulness metrics.
- State of Mind (daily mood) — new in version 1.5. The 1–5 mood you tap on your daily check-in can be mirrored to Apple Health as that day's State of Mind daily-mood sample, sourced to CalmTide. This write has its own contextual permission prompt, shown the first time you save a check-in — it is separate from the mindfulness permission and from everything asked for on first launch. CalmTide never generates mood data you did not enter. If you change a check-in, CalmTide replaces that day's Health sample rather than stacking a second one on top of it.
The same contextual prompt also asks to read daily mood. That read is optional and works in one direction only: it lets a mood you logged in the Health app, or in any other app, stand in for a CalmTide check-in you missed. Your own in-app entry always wins.
Both writes go to your own on-device Health store. Neither is data collection by us: nothing about them is transmitted anywhere, and we never see them. You can decline either permission, or revoke it later in Apple Health → Apps and Services → CalmTide, and keep using breathwork and daily check-ins normally. Apart from these two sample types, CalmTide's use of Apple Health is read-only.
What CalmTide does not do
- No account. You don't sign up, sign in, or give us an email to use the app.
- No analytics or tracking. We don't use third-party analytics SDKs or advertising identifiers.
- No health data uploads. Your Apple Health data and the scores derived from it stay on your device.
- No selling of data. We have never sold user data and never will.
The SolGlow connection
If you also install SolGlow, the two apps can share a small amount of data through a secure App Group container on your device — a shared file readable only by these two apps. This is device-local; nothing is transmitted over the internet.
SolGlow writes summary values such as morning-sun minutes, a morning-rhythm score derived from them, weekly sun average and streak, and your UV and vitamin D estimate. (Through version 1.5 this score was labelled a Cortisol Awakening Response; it was always a proxy calculated from morning-light minutes, and 1.6 renamed it accordingly.) CalmTide writes back a small summary: weekly HPA balance score, baseline trend, weekly MET-minutes, and hard-session count. No raw health data, identifiers, or credentials cross this boundary — only the summary fields above. Removing either app clears the data it wrote.
Purchases
CalmTide Pro is sold through Apple's App Store using StoreKit. Apple processes the transaction; we receive only the entitlement status needed to unlock Pro features. We do not see your payment details. Offer codes are redeemed through Apple's own redemption sheet, and are never tied to a rating or review.
Notifications
If you opt in, notifications (a morning check-in timed to your usual wake time, an evening heads-up before a day with a high load forecast, a wind-down cue after a late hard session, a post-workout nudge, a weekly summary, and a recovery alert) are scheduled locally on your device. Their timing and content are computed on-device and are not sent to any server.
Data control, export & deletion
You control Health permissions any time in Apple Health → Apps and Services → CalmTide.
Export and restore. Profile → Your Data exports your own CalmTide data as a JSON file through the system file exporter, and restores it from a file through the system file importer. No network is involved in either direction. The file goes wherever you send it and nowhere else: nothing leaves your device except by your own explicit share action. The file holds only data you authored in CalmTide — nothing read from Apple Health and no derived estimate — and moods imported from other apps' State of Mind entries are left out on export and refused on restore. CalmTide has no cloud backup or sync.
Deletion. Deleting CalmTide removes all of its local data, including cached snapshots and the values CalmTide wrote to the shared SolGlow container. Data stored in Apple Health — including the Mindful Sessions and State of Mind samples CalmTide wrote — is owned by Health and remains there unless you remove it in the Health app.
Children
CalmTide is not directed to children under 13 and does not knowingly collect data from them.
Medical disclaimer
CalmTide provides wellness estimates based on published exercise-physiology research. It does not measure cortisol directly, is not a medical device, and should not be used to diagnose, treat, or make decisions about any medical condition. The HPA Balance Score, daily load estimate, readiness and weekly balance trend are model-based estimates and may be inaccurate. Always consult a qualified healthcare professional about stress, sleep, exercise, or any health concern. Your use of CalmTide is also governed by our Terms of Service, including its health, warranty, and liability disclaimers.
Changes to this policy
If this policy changes, we'll update the date above and, for material changes, note them in the app or on this page.
Contact
Questions about privacy? Email support@twisteddatastudios.com.