Stress
A 0–100 stress index and a low / moderate / high level. Core metric.
Definition
Stress condenses the pattern of heart-rate variability into a single index that reflects regulatory strain on the body. It is reported two ways: a numeric index and a coarser level.
| Field | Type | Meaning |
|---|---|---|
stress.index | integer 0..100 | Higher means more physiological stress. |
stress.level | low / moderate / high | A coarse bucket for at-a-glance display. |
Range
| Index | Level |
|---|---|
| Lower values | low |
| Mid values | moderate |
| Higher values | high |
Interpret stress as a relative, personal indicator rather than an absolute score. It moves with posture, breathing, caffeine, sleep, and time of day.
Averaging window
Because stress is derived from HRV, it needs the same many clean beats — a
sustained, still capture. In a short or noisy session the stress index may be
null.
Works when
- HRV itself works: still subject, even lighting, enough clean signal.
Does not work when
- HRV is unavailable — too much motion, too short a session, or low signal quality.
Confidence
Stress inherits the top-level signal quality and, like
HRV, has no separate per-metric confidence field. When the signal is unreliable,
both index and level are returned as null.
See the full disclaimer.