What a recovery score can and cannot tell you
A recovery score gathers available overnight records into a simple summary. It cannot make a medical decision or replace what you know about your body.
A score is an interpretation, not a measurement
A recovery score organizes the overnight records that are available into one summary. Depending on what Apple Health recorded and what a device supports, those records can include sleep, heart rate, heart-rate variability (HRV), and breathing rate. Temperature, blood oxygen, and breathing interruptions can be shown alongside your night and do not change a score.
The score is a summary of those available records. It is not a direct measurement of readiness, health, or what your body can safely do.
Your history provides the comparison
Underbark compares available readings with your recent personal history, the records that build up over time. That creates a personal baseline: what is typical for you based on your recent history. It gives a change some context without treating a population average as individualized truth.
A baseline takes time and usable records to develop. Read more about how HRV, resting heart rate, and personal baselines fit together.
Unknown inputs stay unknown
A missing record is not a zero and is not proof that nothing happened. Device wear, charging, permissions, whether the device or app recorded enough information, and unsupported metrics can all leave gaps. Underbark keeps those inputs unavailable instead of inventing precision.
What a zero or calibrating result means
If no input can contribute, the current app can display 0, Calibrating. This is a software calibration state, not a physiological zero or an adverse health finding. It means the app does not yet have a usable scored input.
Seeing it does not mean your recovery was poor, and it is not a reading about your body at all. It usually means the overnight records the score depends on were unavailable for that day. The same state is described alongside Activity Score in why recovery and Activity Score can look different.
Use the score as context
A score can help you notice a pattern and reflect on how you feel. It does not grant permission to train, prescribe an intensity, or override pain, symptoms, professional advice, and your own judgment.
Know where the score stops
If a reading concerns you or you need help deciding what is safe, seek advice from a qualified health professional. For help understanding Underbark's behavior, visit the support page.