Open Stress: HRV Notifier

Open Stress is a privacy-first iPhone wellness app for HRV observations already stored in Apple Health. It turns those sparse readings into on-device views of the latest raw SDNN value, a seven-day personal baseline, a personal HRV level, a separate personal stress estimate, and 7/30/90-day trend summaries.

The app keeps individual HRV readings for today and the previous six local dates. Older readings are stored as daily averages. Personal estimates use retained raw readings; daily averages are not treated as individual samples.

The app is designed around observations, not continuous monitoring. Today shows raw HRV in milliseconds, not a percentage. Trends reports counts and shares of observations rather than inventing stress duration. Insights explains freshness, context, and baseline coverage. General wellness information includes visible source links to Apple documentation and official WHO/CDC guidance. Sources & methods explains the references and the limits of the app-designed estimate.

Open Stress reads Apple Health HRV. When iOS delivers a new qualifying observation, optional notifications can provide a local, timestamped update. The app has no account, product server, ads, or third-party analytics. Data are completely local on your iPhone. There is no account, sign-in, backend servers. As all apps should be.

Start seven days of full app access without a subscription or automatic charge. After this local seven-day period, continued access requires an auto-renewable annual subscription or a restored purchase.

The U.S. annual subscription price is $9.99 per year, and the App Store shows your localized price and applicable terms before purchase. Any Apple subscription introductory offer is separate from the local app-access period; Apple determines offer availability and eligibility. Unless canceled at least 24 hours before the current subscription or applicable introductory-offer period ends, the subscription renews automatically each year. You can manage or cancel it in App Store account settings. Restore Purchases is available in the app.

Privacy Policy: https://kiskir.dev/projects/open-stress/privacy

Terms of Use: https://kiskir.dev/projects/open-stress/terms

Disclaimer: All data, analyses, and suggestions are for general reference only, not medical advice or clinically validated, personalized recommendations. HRV observations come from Apple Health. The personal estimate is an app-designed, unvalidated wellness heuristic. First-party Apple documentation and official WHO/CDC general guidance do not validate that estimate, explain an individual reading, or determine a suitable action for you. Do your own research and consult a qualified doctor or other appropriate professional when needed. Do not use this information as a basis for action or to replace or delay professional care.