The Two Numbers Behind Almost Every Garmin Score: HRV and Resting Heart Rate

Two numbers quietly run your Garmin

Your Garmin shows you a dozen scores: Stress, Body Battery, Training Readiness, Sleep Score, HRV Status. It looks like a lot to keep track of, but almost all of them come back to just two measurements. Understand those, and the rest of your watch suddenly makes sense.

Number one: HRV

Heart rate variability is the tiny variation in time between your heartbeats. Your heart doesn't tick like a metronome: one gap might be 0.85 seconds, the next 0.92.

• More variation means your nervous system is relaxed and recovering
• Less variation means your body is under pressure: stress, fatigue, illness, alcohol, a hard training block

And a lot of your Garmin is built on it:

• Stress: your all-day stress score is calculated from your heart rate and HRV
• Body Battery: whether it drains or charges depends largely on your HRV-based stress, together with sleep and activity. That's why it charges overnight and drains on a busy day
• Training Readiness: HRV Status is one of its biggest inputs, next to sleep, recovery time and training load

What matters isn't the number itself, which differs hugely between people, but how it compares with your baseline. That's exactly what HRV Status shows you overnight.

Number two: resting heart rate

It's the simplest number on your watch, and one of the most useful. When your body is dealing with something, like bad sleep, alcohol, too much training, or an infection on the way, your resting heart rate creeps up. Often a day or two before you feel anything yourself.

Again, compare it with your own normal. A resting heart rate of 58 means nothing on its own, but 58 when you're usually at 50 is your body telling you something.

When both point the same way, listen

One number moving on its own is often noise: a glass of wine, a warm bedroom, a late meal. Both moving together is a signal. So the rule is simple:

If your resting heart rate is clearly above your normal and your HRV has dropped below your baseline range, skip the hard workout and go for an easy walk instead.

A hard session on a stressed body doesn't make you fitter. Training only works when you recover from it, and here you're adding load to a body that's already busy. It just digs the hole deeper. Take the easy day, and the hard session will be worth more tomorrow.

Go deeper

• When an HRV drop is worth paying attention to
• Everything about resting heart rate
• What Training Readiness is actually made of
• Combining HRV, resting heart rate, respiration and blood oxygen into a daily illness score

Your Garmin is not a medical device. If your numbers stay off for days, or you feel unwell, talk to a doctor.