Blog
State of Mind in Apple Health: a mood you log yourself, shown next to the weather
Apple Health's State of Mind is a mood you log yourself — not a sensor reading and not a diagnosis. MeteoHealth only reads it from Apple Health and shows it next to the weather.
Measuring heart rate with your phone camera: how it works, and how accurate it really is
Camera-based heart rate uses photoplethysmography, the same optical principle as pulse oximeters. Here's the honest picture of what it can and can't estimate.
VO₂ max, blood oxygen, and breathing rate: what your Apple Watch measures and MeteoHealth shows
Apple Watch measures blood oxygen and estimates breathing rate and VO₂ max; MeteoHealth reads them from Apple Health and shows them next to the weather — it never measures them itself.
Wrist temperature during sleep: what Apple Watch is actually tracking
Apple Watch reports a nightly wrist-temperature deviation from your own baseline, not your body temperature. What that signal reflects — cycle, sleep, feeling unwell — and what it doesn't.
HRV explained: what heart rate variability is and why it matters
What heart rate variability actually measures, what makes it rise and fall, how accurately a wearable like Apple Watch estimates it, and why your own trend matters more than any single number.