Garmin’s stress level is HRV turned into a score, not a separate measurement. The owner’s manual says the watch “analyzes your heart rate variability while you are inactive to determine your overall stress”, on a scale from 0 to 100. Body Battery then builds on that score, and HRV Status shows the overnight HRV itself against your own baseline Baseline Your own usual HRV level and range, built from weeks of readings taken the same way. Comparing a reading with your baseline says more than comparing it with other people. More about Baseline .
One signal, three displays
| Garmin feature | What Garmin says it uses | Scale |
|---|---|---|
| Stress level | Heart rate variability while you are inactive | 0 to 100: 0–25 resting, 26–50 low, 51–75 medium, 76–100 high |
| Body Battery | Heart rate variability, stress level, sleep quality and activity data | 5 to 100: 5–25 very low, 26–50 low, 51–75 medium, 76–100 high reserve |
| HRV Status | Overnight HRV, as a 7-day average against your baseline range | Balanced, Unbalanced, Low, Poor |
| Training Readiness | Sleep score, recovery time, HRV status, acute load, sleep history, stress history | 1 to 100 |
Every row starts from the same heartbeat gaps. Stress is HRV read during the day while you are still; HRV Status is HRV read during sleep; Body Battery and Training Readiness mix those with sleep and activity. Garmin does not publish how HRV maps onto the stress scale or how the inputs are weighted, so none of these can be recomputed from the others. The score builder lays out each maker’s inputs side by side.
Why “inverted HRV” is close but not right
The intuition that stress is HRV upside down is roughly correct: lower HRV reads as higher stress, and the manual notes that training, physical activity, sleep, nutrition and general life stress all move it. But the score is not a simple flip of the millisecond value. It is read only while you are inactive, the scale is the maker’s, and the mapping from milliseconds to the score is not published, so it can change after an update without your HRV changing. See can a software update change my HRV.
What the stress score does not know
The algorithm sees heartbeat gaps and nothing else. Anything that lowers HRV for an hour reads as stress: a big meal, caffeine, alcohol, a cold coming on, a hot room, an exciting film, standing in a queue. Anything that raises it reads as rest, including the calm after a hard workout once your heart rate has settled. That is why the manual ties stress to physical and life factors rather than to mood. The lesson on HRV, stress and breathing explains the link between the nervous system and the gaps, and the stress page covers what the research shows.
How to read it
- Use the day’s average, not spikes. A single high reading after lunch means little.
- Compare with your own usual day. A week of higher average stress with poorer sleep is the pattern worth noticing.
- Read it next to HRV Status. If overnight HRV is in your range and daytime stress is high, the day was busy but the body is coping. If both are off, look at load, sleep, alcohol and illness.
- Wear it at night. The manual says that for best results you should wear the device while sleeping; the overnight readings feed HRV Status and Body Battery.
When to talk to a doctor
A stress score cannot diagnose anxiety, burnout or heart problems. Talk to a doctor if you feel persistently stressed, anxious or exhausted, or if you have palpitations, chest pain, dizziness or fainting, whatever the score shows.