Last updated: September 22, 2026

Lintra is a small app with no account, so most questions fall into one of the handful below. If yours is not here, email ootssu@ootssu.com.

Why is there no data yet?

Lintra can only work with heart-rate-variability samples your Apple Watch has already recorded in Health. If you don’t wear a Watch, or haven’t worn one recently, there is nothing for Lintra to read.

Even with a Watch, Lintra needs time: your baseline is built from the preceding 28 days of HRV samples, so a freshly installed Lintra, or a Watch worn only occasionally, will show little or nothing at first. Wearing the Watch consistently, especially overnight, is what fills the baseline in fastest.

Why don't any stress-cause candidates appear?

Two separate things have to be true before Lintra names a candidate:

• Calendar access has to be granted. It is optional — if you declined it, or revoked it later in iOS Settings → Privacy & Security → Calendars, Lintra can detect HRV dips but cannot match them against anything.
• The pattern has to repeat clearly. Lintra’s confidence bar is deliberately high — a single overlap between a dip and an event is never enough. It only names a candidate once your HRV dipped around the same recurring event in most of the weeks it happened.

If both are true and nothing still appears, it may simply mean your stress this month has no clean recurring calendar event behind it. That is Lintra declining to guess, not a bug.

Restoring your subscription

Lintra’s subscription is tied to your Apple Account, not to a device. On a new phone, or after reinstalling, tap Restore on the paywall or in Settings. As long as you are signed in to the Apple Account that subscribed, it unlocks again at no extra charge.

If Restore doesn’t find it, check that you are signed in to the Apple Account that made the purchase — a different Apple Account cannot see it — then check your network connection, since verifying a subscription needs the internet.

Cancelling your subscription

Open Settings › [your name] › Subscriptions on your iPhone, choose Lintra, and cancel. Cancelling stops the next renewal; it does not refund the current period, and you keep access until it ends.

Deleting your data

Everything Lintra computes is on your device. Settings → Delete My Data inside the app removes it, and deleting the app removes its storage entirely. There is no account and no server copy, so there is nothing to request from us and no deletion request to file.

Refunds

App Store subscriptions are refunded by Apple, not by us. Request one at reportaproblem.apple.com.

A note on what this app is for

Lintra finds a correlation between your HRV and what repeats on your calendar. It is not a medical device and does not diagnose, treat, or prevent any condition. If something about your heart or your stress worries you, please take it to a healthcare professional rather than to a candidate named in an app.

Contact

Email ootssu@ootssu.com. Telling us your iPhone and Apple Watch models and iOS/watchOS versions makes a data or detection problem much faster to work out.