How we write wellness pages
Sources, review dates, and the limits of an app company writing about overnight biometrics.
Who writes this
Guides, science notes, and comparison pages are written by Early Signal. There is no named clinician reviewing each page. We say that on purpose. A wellness page should not borrow medical authority it does not have.
What we publish
Education about overnight biometrics from Apple Watch—wrist temperature, breathing rate, HRV, resting heart rate, and sleep—and how the app turns those into a personal status and low-risk rest actions. Comparison pages describe the job each product documents. None of this is medical advice, a diagnosis, or a prediction that you will feel run down.
Sources
Guides cite public documentation: Apple’s support articles for sleep, respiratory rate, and Vitals, MedlinePlus for heart rate variability, and each competitor’s own help pages when we describe their product. We link the source. We do not imply that Early Signal has been validated as a medical device.
Review cadence
Each guide and comparison shows a last-reviewed date near the title. We revisit these pages at least every 12 months, and sooner when a cited document changes or a reader reports a factual error. The date is the review date, not a claim that a new study appeared that day.
What we will not claim
We do not invent prices, ratings, download counts, or unlisted features for Apple, Oura, WHOOP, Fitbit, or anyone else. We do not name diseases in instructional status copy. We do not tell you to skip care because an app says Typical.
Corrections
If a page is wrong, out of date, or missing a limit, email . We correct factual errors on the page and update the reviewed date.
The method is summarised on Science. Guides live under Guides.