How each brand builds its recovery or readiness score

The table

What the table says

HRV and resting heart rate show up in every row. They are the signals that change when your body is under strain, and wrists and fingers can measure them overnight. Sleep is the third constant. A score that ignores a bad night would not match how people feel.

The meaningful differences are in what each adds. WHOOP adds respiratory rate and says a large change can flag illness. Oura adds body temperature and a recovery index of how quickly your heart rate settles. Garmin adds training load, which makes its score part recovery and part workout planner. Google keeps it narrowest.

Garmin and Amazfit also offer a second, all-day gauge (Body Battery, BioCharge). Those rise and fall during the day, so they answer a different question from a morning recovery number. Pulse's counterpart is Energy Bank.

Why the numbers cannot be compared

Each score is judged against your own baseline: WHOOP compares HRV to a 30-day baseline, Garmin builds an HRV range over about three weeks, Google uses up to 30 days. A 65 from one and a 65 from another are different statements. Zones differ too: WHOOP's green starts at 67, Google's High at 65.

What does carry across is the shape. If every score you own drops after a short night, heavy drinking or a cold, the physiology is doing what it should. If one drops and another does not, read their inputs before trusting either. For stuck-low Fitbit numbers, see this checklist.

Three things worth knowing about each vendor's description

• WHOOP's current Recovery page lists more inputs than older explainers do: skin temperature, SpO2 and cycle phase appear on the current page. Read the current page, not a years-old summary.
• Google's Readiness page has changed too. Older Fitbit material listed activity as an input; the current page lists HRV, resting heart rate and recent sleep.
• Garmin's tier names and cut-offs for Training Readiness vary between manuals and devices, so check your own device before relying on any band.

What Pulse is, and is not

Pulse is a free, open-source app that computes its own scores from Google Health data. It does not read Google's Readiness (the API has no such type) and it has been tested on the Fitbit Air only. It publishes its method so you can read exactly how a number is made. For the scores of two bands side by side, see Fitbit Air vs Garmin Cirqa and Fitbit Air vs Oura Ring.

Sources

1. Google Health Help: Daily Readiness
2. WHOOP support: Recovery
3. Garmin owner's manuals and support: Training Readiness, HRV Status, Body Battery, Sleep Score (read via search excerpts)
4. Zepp Health: technology and algorithm pages (read via search excerpts)
5. Oura: Readiness Score
6. Gadgets and Wearables: Understanding Samsung's Energy Score
7. Apple Newsroom: Introducing Apple Watch Series 12 (September 2026)
8. AppleInsider: how Sleep Score works on Apple Watch with watchOS 26