From Apple Health to a rare heads-up
Early Signal measures personal variations in overnight biometric baselines from Apple Health to suggest low-risk rest actions. No new ring and no account — compared only to you.
1. Overnight Health sync: the app reads native biometric samples Apple Watch has stored in Apple Health. 2. Personal baseline: the algorithm maps your usual pattern from your own nights. 3. Early rest-day heads-up: if anomalies move past your usual variance, the app suggests low-risk rest actions such as rest, extra fluids, and an earlier bedtime. This is not a diagnosis.
Four steps
- 01
Grant Apple Health access
Allow read-only access to wrist temperature, respiratory rate, HRV, resting heart rate, sleep, and workouts. Early Signal never writes to Health. If access fails, the app stays on this step with instructions and a Continue anyway option so you are not stuck.
- 02
Import nights you already have
On first open, the app reads history already on your Watch. Many people unlock a personal baseline immediately once enough valid HRV and RHR nights exist.
- 03
See morning status
Each day Today shows Typical, Slightly off, or Off from usual. After a hard workout or a logged context, generic patterns can show as Explained by context. If overnight HRV or resting heart rate is missing, you get No verdict today instead of a guess. On alert days, Today shows two or three rest suggestions; See why opens the detail screen. Temperature and breathing lead when present; if your Watch has never recorded wrist temperature, Temp is omitted from the ring.
- 04
Watch Trends and rare alerts
Trends charts lead with wrist temperature and breathing when your Watch has them, then HRV, resting heart rate, and sleep. Free trends cover 14 days; history covers 30. Off from usual push notifications are capped at most once every 3 days. Pro is never auto-shown on an Off from usual morning. Widgets show status at a glance without reading HealthKit themselves.
What Today shows
One status, a couple of actions on alert days. See why is the detail screen, not a second Today
Typical
Quiet day
Slightly off
Ease off
Off from usual
Rest today
Explained by context
Workout or logged context
Learning
Baseline still forming
No verdict
Data missing
Five signals, in order
Temperature and breathing lead when your Watch has them. If wrist temperature has never been recorded, Temp is omitted from the ring. Missing data never looks in range.
01
Wrist temperature
Lead
02
Breathing rate
Lead
03
HRV
Support
04
Resting heart rate
Support
05
Sleep
Context
Want the methodology? Read Science. Prefer practical explainers? Browse Guides. Comparing approaches? See Alternatives.
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