YOUR NUMBERS, UNDERSTOOD
A reading becomes more useful when you can see where it belongs in your own history.
A comparison with your own recent readings from a compatible source and method. Teeras shows the middle 80% of at least 14 comparable prior nights within a 28-day window. It is a descriptive range, not a target or a clinical reference range.
A measurement and your experience describe different parts of your day. Teeras keeps both visible: your recorded HRV and sleep, the feeling you choose, and any words you add. It does not decide that one makes the other wrong.
No. Teeras reads available HRV and sleep data with your permission. It does not turn HRV into a live stress score, diagnose stress, or tell you how you should feel.
Teeras compares readings with the same source, method, version and recorded timezone. SDNN and RMSSD are different HRV methods; Teeras keeps them separate. A change of device or method may mean building a new comparable history.
A 2022 study of information workers found weak alignment between wearable HRV and perceived stress. Its sample and measurement approach limit generalization; it does not validate Teeras. It supports keeping your reported experience alongside a measurement.