Sleep signal guide
Heart rate variability (HRV)
Direct answer
Direct answer
HRV is the variation in time between heartbeats. A personal overnight trend can add context about recovery and stress, but one value cannot diagnose a condition or be compared cleanly across every device.
How to use it
- ✓Compare against your own baseline
- ✓Look for repeated changes
- ✓Pair the number with symptoms, training, alcohol, illness, and sleep
What it cannot prove
- !Not a diagnosis
- !Device methods differ
- !One unusual night is weak evidence
Sources and further reading
- 1