Personal performance log

HRV Field Log

Measure consistently. Read your own trend.

Phone sensor

Measure HRV with your camera

Rear camera + flash · fingertip pulse recording · 60 seconds

CAMERA READY

Sit still and cover both the rear camera lens and flash with the pad of your fingertip. The camera records tiny brightness changes from blood flow, then estimates RMSSD from pulse-to-pulse timing. Use an HTTPS website in Chrome on your phone.

Finger over lens + flash
Time left60s
Live samples0
FlashOff

Ready. Warm your hands if cold, rest your hand and phone on a table, then start.

Accuracy: this is camera-derived pulse-rate variability (PRV), not an ECG measurement. Camera frame rate, movement, finger pressure and cold hands can distort beat timing. Use it for consistent personal trends, and keep it separate from wearable/ECG RMSSD. Video frames are processed in memory on your phone and are not uploaded or stored; only the calculated reading is saved if you tap Save. If quality is poor, the app will ask you to repeat rather than save a number.

Recovery signal / personal baseline

Know your pattern.
Not someone else's number.

HRV is most useful when measured under the same conditions and compared with your own history. Log a reading or import your wearable data to get started.

NO READINGS LOGGED YET
Latest HRV
—ms
Add a reading to begin.
Baseline building
Aim for at least 5 prior readings of the same HRV metric.
30-day personal baseline
—
Same metric only
7-day median
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No recent readings
Readings logged
0
Stored on this device/browser

HRV trend

Values are shown by measurement time.

Your history will appear here after you log or import readings.
HRV reading Personal baseline (when enough history exists)

Log a reading

Keep timing, posture and measurement conditions consistent.

Enter the value exactly as shown by the device.

How to use your signal

Make comparisons that hold up.

Measure at a consistent time, ideally after waking and before caffeine, food or training.
Compare like with like. RMSSD, SDNN and vendor-specific HRV scores should not be mixed into one baseline.
A lower-than-usual value can reflect poor sleep, stress, alcohol, illness, dehydration or training load. One reading alone is not a diagnosis.
Interpretation rule: the app uses your own recent median, not population norms. It does not issue a medical or training-readiness diagnosis. Look at multi-day patterns alongside how you feel.

Reading history

Most recent first. Values preserve the metric recorded.

Import wearable data

JSON or CSV file

Choose an export from your wearable or a file generated by this app. JSON records are auto-detected where possible. For CSV, map the date and HRV columns after selecting the file.

No file selected.
Import tip: a CSV with columns such as Date and HRV is usually detected automatically. If a file contains several numeric metrics, select the actual HRV column yourself.

Backup & portability

Keep a copy before changing phones or browsers.

Your entries are stored in this browser's local storage. The webpage can be hosted on a server, but it does not upload health data to that server. Export JSON for a full backup or CSV for analysis.

Privacy: no account, analytics, external libraries or network calls are used. Browser storage is separate for each browser/device and website address. Import your JSON backup on another device to move the log.