Corio
Free tool

Why did my HRV drop?

Is it you, your habits, or the device? Drop your Oura export and see if last night's drop is real or just normal noise, plus the likely suspects ranked from your own nights: alcohol, late meals, training, weekday habits, cycle, or a new ring.

Your file never leaves your device. It's read by JavaScript in this browser tab. Nothing is uploaded and there's no account. Load the page, turn off Wi‑Fi, and it still works.
The sample is synthetic, not a real person.

How it works

  1. 1 · ExportIn your Oura web account (membership hub): Export data → Request your data. Oura emails you a .zip.
  2. 2 · Drop it hereThe whole .zip is fine. The checker finds the HRV, tags, activity and temperature files by itself.
  3. 3 · Read your suspectsEach night is compared with your own previous two weeks. Patterns with fewer than 5 nights get "not enough data", not a guess.

This is an educational tool, not medical advice, and it doesn't diagnose anything. If you feel unwell, talk to a doctor. Works with your Oura export; Corio is not affiliated with or endorsed by Oura Health Oy. Oura is a trademark of Oura Health Oy.

Questions

Why did my HRV drop?

The usual suspects for a one-night drop are alcohol, a late or heavy meal, a hard workout the day before, going to bed late, a hot room, getting sick, and stress. For many people HRV also dips in the days before a period. A drop that starts on one exact day and stays often comes from the device: a new ring, a different finger, or a firmware update. The checker ranks these suspects using your own nights.

Is a drop in HRV bad?

Usually not. HRV naturally swings 10–20% from night to night, so one low night is mostly noise. What matters more is your 7-night average staying below your own normal range. If you feel unwell or a low HRV comes with symptoms, talk to a doctor.

I feel great, but my HRV and readiness are low. Why?

Both can be true. HRV reacts to things you may not feel, like alcohol, a late meal or a warm bedroom. It can also move because of the sensor: a new device, a different fit, or a software update. If the drop began on one specific day and never recovered, check the device first.

How do I export my Oura data?

Sign in to your Oura web account (membership hub), choose Export data → Request your data, and Oura emails a download link to a .zip. Drop the whole .zip here, or just the sleep file plus the tags file.

Is my health data uploaded anywhere?

No. The file is read inside your browser tab and never sent to a server. The page only counts anonymous visits (like "someone opened the page"), never any health data.

Does it work with Apple Watch or WHOOP?

Yes. Apple Health's export.zip or export.xml works, and the checker spots a new watch or a watchOS update. Apple reports HRV as SDNN, which runs higher than Oura's RMSSD, so compare it only with itself. WHOOP's data export works too (physiological_cycles.csv and journal_entries.csv).

What is a normal HRV?

There's no single normal number. HRV depends on age, genetics, fitness and the device. That's why the checker only compares you with your own 30- and 60-day baseline, never with other people.