The observer's body
Biometric data from the artist's activity tracker, read alongside the sea. The same four time-scale layers applied to a human body: what is happening now, what is usual for this time of day, what has been true over weeks, what is normal for this person. Data accumulates from the moment the system starts running.
Today
Daily summary fetched from Garmin Connect — resting heart rate, sleep score, body battery, stress, steps, SpO2, HRV. One value per day per metric.
Slow layer
Daily values over the past 30 days. Detects multi-week trends: is resting HR gradually rising? Is sleep quality declining? Is body battery consistently low? Accumulates over time — more meaningful as more days are collected.
Baseline
Personal mean and standard deviation computed from all available history. What is normal for this specific body — not population averages. The baseline updates as more data accumulates. A reading is salient when it deviates from this personal norm.
Intraday layer — coming soon
Heart rate, stress, and body battery at sub-hourly resolution. Will enable diurnal comparison: is HR at 14:00 today higher than at 14:00 yesterday? Data begins accumulating from when intraday logging is enabled.