You wake up, check your watch, and it says your HRV is low. Now you have to decide whether that means skip the session, or nothing at all. Most mornings, it means nothing at all.
What HRV is
Your heart doesn't beat like a metronome. The gap between beats changes slightly from one beat to the next, and HRV measures how much. When you're rested, that variation tends to be higher. When you're stressed, tired, ill or short on sleep, it tends to drop.
Watches usually measure it overnight, which is the most consistent time to do it.
Different devices measure it in different ways, so the number on one watch won't match another. Pick one, wear it the same way every night, and only compare it with itself.
Why one number is noise
HRV moves around a lot from night to night for reasons that have nothing to do with training: a late meal, a glass of wine, a hot room, a bad dream, travel. One low reading is far more likely to be one of those than a sign you're overtrained.
It's also personal. Comparing your number with a friend's, or with a chart online, tells you nothing. A low HRV for one person is a high one for someone else.
Training itself moves it too. A hard session or a big weekend can pull HRV down for a night or two. That's not a warning. It's the training doing its job, and it should come back as you recover.
Read the baseline, not the night
The useful view is your own trend: a rolling average over about a week, against what's normal for you over the last month or two.
- A single low night: note it, train as planned unless you feel rough.
- Several nights in a row below your usual: ease off, sleep more, and check for a cold coming on.
- A slow climb over weeks while training is going well: a good sign, but not one to chase.
Resting heart rate is HRV's plainer cousin and often tells the same story. A morning resting heart rate a few beats above your usual, for a few days, is worth paying attention to.
Give a new device a few weeks before you trust its baseline. Your usual has to exist before anything can be below it.
Where it's useful
HRV is best as a tiebreaker. If your plan says hard and your legs say no, a run of low readings backs your legs. If you feel fine and the trend is normal, one bad night isn't a reason to skip.
It's also good at catching illness early. A drop with a scratchy throat is a much stronger signal than either on its own.
What it can't do is tell you how fit you are, or whether you'll race well. Some athletes race their best with a mediocre reading on the morning. Treat it as one voice in the room, not the one that decides.
How LankFit shows it
If you connect Garmin, your HRV, resting heart rate, sleep and weight come in automatically and refresh every few hours. The Vitals page shows your latest reading, your usual, and the difference, with a plain sentence on what it means, so you see the trend before the single number.
And if a low run of readings turns into a cold, log it. Your charts and your readiness then know why the week went quiet.
The rest is up to you, which is how it should be. The numbers sit next to your training so you can see both at once. The decision about this morning's session is still yours.