HRV: what it actually tells you

Heart-rate variability — the variation in time between consecutive heartbeats — is a window into your autonomic nervous system. High variability generally signals a recovered, adaptable system. Low variability often means your body is under load, whether from training, illness, stress, or poor sleep.

Why absolute numbers mislead

One person’s healthy HRV can be another person’s warning sign. Comparing your number to a friend’s is meaningless. What matters is your trend against your own baseline — which is exactly why LockIn90 calibrates to you before it says anything.

Reading the trend, not the day

A single low morning is noise. A three-day slide is signal. We weight recent readings against your rolling baseline so a single bad night does not blow up your score, but a genuine downward trend gets your attention early.

• Measure at the same time, ideally on waking, for consistency.
• Expect day-to-day swings — focus on the multi-day direction.
• Context matters: alcohol, late meals, and stress all suppress HRV.

Used well, HRV is less a crystal ball and more a smoke detector: it tells you something is changing before you consciously feel it.