# Tonus: HRV Readiness — Recovery, with error bars

> Recovery, with error bars (iPhone/iPad app by BERKE KAHRAMAN.)

- Source: https://appshunter.io/ios/app/tonus-hrv-readiness/id6806266110 (this page in markdown: same URL + `.md`)
- Developer: [BERKE KAHRAMAN](https://appshunter.io/developer/1843240615)
- Category: Health & Fitness, Medical
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 2 MB
- Languages: American English, German (Germany), Japanese, Turkish
- Released: 2026-09-15
- Data updated: 2026-09-20
- User reviews in markdown: https://appshunter.io/ios/app/tonus-hrv-readiness/id6806266110/reviews.md

## What is Tonus?

With your permission, Tonus reads existing heart rate variability (HRV), resting heart rate and respiratory rate records from Apple Health. It uses available readings for personal baselines and a daily readiness range. You can also continue without connecting to Health.

READINESS AND UNCERTAINTY
Tonus shows readiness as a range and makes uncertainty visible. If there is not enough data for a readiness result, the app explains what is missing.

YOUR PERSONAL BASELINE
Tonus shows the baseline calculated from your recent measurements and tracks whether it shifts. You can pin the current baseline while continuing to see drift. Each baseline needs usable measurements from at least 14 days.

NO SERVER, NO ACCOUNT
Tonus performs calculations locally on each iPhone and Apple Watch. No account, no sync service, no analytics. Tonus does not upload your health readings.

Tonus is not a medical device. It does not diagnose, treat or prevent any condition.

TONUS HISTORY (OPTIONAL SUBSCRIPTION)
History is an optional subscription, offered monthly or yearly. Eligible new subscribers can start with a 3-day free trial. The price, the trial and your eligibility are shown by the App Store before purchase. Payment is charged to your Apple Account at confirmation. Subscriptions renew automatically unless auto-renew is turned off at least 24 hours before the current period ends; manage or cancel in your Apple account settings. Measuring — today's range, the decision, your baselines and their night counts — stays free.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://berkemd.github.io/norea/tonus/privacy.html

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Tonus History | $2.99 | per month |
| Tonus History | $24.99 | per year |



## Version history (last 3 releases)

### 1.3 — 2026-09-19

Tonus can now ask what you think of it — and it asks in a way most apps do not.

The question only appears when there is a measured readiness answer on screen. It never appears over “I can’t tell yet.” It waits until Tonus has actually decided on at least five separate days, asks once per version, and then stays quiet for four months.

Asking for a rating in a moment when the app could not do its job would be asking to be paid for something it did not deliver. So it doesn’t.

Nothing else changed: the baseline, the band, the change layer and the history are exactly as they were.

### 1.2 — 2026-09-19

Tonus put your baseline on screen because no other readiness app does. This version lets it move.

History — a new tab — draws six months of daily readiness as ranges, not points, and leaves the days you did not measure empty. Under it, your baselines themselves as a line over time, with the days they were drifting marked in orange. And the last 28 nights measured against the 28 before them, per signal, with a plain answer when there are not enough nights to say.

Every day in those charts is computed the way that day would have been: only from nights known by then. A history that knows the future is not your history.

Today's range, the decision behind it, your baselines and their night counts stay free, as they were.

### 1.1 — 2026-09-15

No release notes.

## More apps by BERKE KAHRAMAN

- [Forgn: Prior Art Search](https://appshunter.io/ios/app/forgn-prior-art-search/id6761314575)
- [POYWX: Signal Cascade](https://appshunter.io/ios/app/poywx-signal-cascade/id6777477818)
- [Skry: Sky Readings & Journal](https://appshunter.io/ios/app/skry-sky-readings-and-journal/id6790419436)
- [Daylume: Golden Hour & Sun](https://appshunter.io/ios/app/daylume-golden-hour-and-sun/id6796813768)
- [Trailhome: GPS Return](https://appshunter.io/ios/app/trailhome-gps-return/id6796813984)
- [Rodewatch: Anchor & Race](https://appshunter.io/ios/app/rodewatch-anchor-and-race/id6796814335)

All apps by BERKE KAHRAMAN: https://appshunter.io/developer/1843240615

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-20.*