Privacy Policy
The short version. Rheostat collects nothing. It has no servers, no accounts, and no analytics. The app makes no network requests at all. Your health data is read from Apple Health, processed on your iPhone, and stored only on your iPhone.
This policy explains how Rheostat ("the app") handles your information. Rheostat is published by Lacaro Ventures LLC ("we", "us"), 5900 Balcones Dr, Ste 100, Austin, TX, United States.
Information we collect
None. We do not collect, transmit, sell, rent, or share any personal information or health data. We have no ability to see your data — there is no server for it to reach.
Specifically, Rheostat contains:
- No analytics or telemetry SDK
- No crash reporting service
- No advertising SDK, ad identifiers, or tracking of any kind
- No third-party libraries that transmit data
- No user accounts, sign-in, or cloud sync
The app makes no outbound network requests whatsoever. You can verify this by using it in Airplane Mode — every feature works normally.
Health data
With your explicit permission, Rheostat reads the following from Apple Health in order to calculate your Readiness and Strain scores:
- Heart rate, resting heart rate, heart rate variability, and heart rate recovery
- Sleep analysis
- Respiratory rate and wrist temperature during sleep
- Steps, active energy, exercise and stand time, and workouts
- VO₂ max
- Your date of birth — used only to estimate a maximum heart rate when we haven't observed one from you
Rheostat does not read blood oxygen, location, or anything else not listed above.
This data is read on demand, processed on your device, and used only to produce the scores and charts you see in the app. It is never uploaded, never shared with us, and never shared with any third party.
Rheostat does not write to Apple Health during normal use.
You can review or revoke these permissions at any time in Settings → Health → Data Access & Devices → Rheostat. Revoking access will stop the app from producing new scores.
What's stored on your device
- Calculated scores and baselines, kept locally so the app doesn't recompute your history on every launch.
- Your settings, such as notification time and algorithm preferences.
- A diagnostic log recording app activity for troubleshooting. It stays in the app's private storage and is size-limited. It is only ever shared if you deliberately export and send it to us for support — we cannot access it otherwise.
All of this is removed when you delete the app.
Subscriptions and payment
Subscriptions are sold and processed by Apple through the App Store. We never see or handle your payment details. Apple provides us with aggregate, anonymised sales reporting — it does not identify individual customers. Apple's handling of your purchase is governed by Apple's Privacy Policy.
Notifications
If you enable them, Rheostat schedules a daily reminder locally on your device. Notifications are generated on your iPhone and are not sent through any server.
Children
Rheostat is not directed at children under 13, and we do not knowingly collect information from them. Since we collect no information from anyone, this is a statement of intent rather than a data-handling practice.
Your rights
Regulations such as the GDPR and CCPA give you rights to access, correct, export, and delete personal data held about you. Because we hold no data about you, there is nothing for us to produce or erase. Your health data belongs to you and lives in Apple Health, where you control it directly. Deleting the app removes everything Rheostat has stored.
Changes
If this policy changes, we'll update this page and revise the date above. Material changes will also be noted in the app's release notes.
Contact
Questions about privacy: support@lacaroventures.com
Lacaro Ventures LLC
5900 Balcones Dr, Ste 100
Austin, TX, United States