HRV
heart rate variability
The variation in time between consecutive heartbeats — an indirect indicator of nervous-system readiness.
The heart does not beat like a metronome. Even at a calm 60 beats per minute the gaps between beats are not exactly one second — 0.95 s here, 1.05 s there. That variation is HRV.
High variability usually means the parasympathetic branch of the nervous system has the upper hand, i.e. recovery. Low means the sympathetic branch does, i.e. mobilisation. And the body mobilises for more than training: infection, alcohol, a bad night and work stress lower HRV just as a hard session does.
The most common measure is RMSSD, in milliseconds. Absolute values differ so much between people that comparing yourself to anyone else is meaningless. What matters is the deviation from your own baseline.
How to read the values
What to do about it
- Measure daily at the same time, ideally right after waking, still lying down.
- Do not react to a single reading. What matters is the 3-7 day trend against a 28-day baseline.
- On a sustained drop, swap the quality session for an easy one rather than skipping training entirely.
A common misconception
“High HRV always means I am in good shape.”
Very high HRV can also signal parasympathetic overreaching after a long block of hard training. The number alone is not enough — read it alongside how you feel and your resting heart rate.
Related terms
See these numbers on your own data
In the app every indicator comes with an explanation of what it means in your case and what we suggest doing next.
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