New wearable: compare the HRV trend carefully
A new wearable often brings new features. At the same time, your measurement series can change. If your HRV trend suddenly looks different after the switch, that is not automatically progress or a setback in your fitness. First check whether you are comparing the same kind of measurement under similar conditions.
Mark the switch in your history
Note the date you first wore the new device overnight. Check in Apple Health when it started writing entries. If the old device's app is still active, two sources may keep writing. What that means for your trend is explained in Understand multiple Apple Health sources.
Check the metric and timing
Apple stores HRV in Apple Health as SDNN. Other devices often use RMSSD, a differently calculated metric on a different scale (more in SDNN vs RMSSD). Even with the same metric, timing and frequency can differ: one watch measures several times a night, another less often. Compare the source and the timing of entries before setting two numbers against each other.
What LeibFit does when you switch
If you move from one watch to another and both write to Apple Health, you do not need to change anything in LeibFit. The app reads values regardless of device. Your personal baseline from the last 30 days simply continues, and the new nights blend in over time. For the first weeks after a switch, the baseline therefore still contains values from the old device. A jump in recovery during that time may come from the device rather than from you.
The Amazfit Helio Strap works differently: you choose in the app whether recovery takes its night values from the watch or from the band. Because watch and band calculate HRV differently, LeibFit never mixes the two. When you switch to the band, the app shows "New source: … more nights" until seven nights from the band are available. Switching back to the watch has no waiting period, because the Health nights are already there.
Do not delete your history too soon
Switching devices is no reason to remove your Health history. The older entries show the path so far. Keep the switch date in mind when comparing weeks before and after. Old and new recordings do not have to share the same basis.
Watch the new routine
Check that the values recovery needs actually arrive from the new device: HRV, resting heart rate and sleep are separate categories. A complete data path is more useful than a nicer single reading. How to check this for a specific device is covered in Check wearable compatibility for recovery apps.
Frequently asked questions
Is a higher HRV after switching automatically better?
No. Check the metric, timing and source before reading the difference as a change. When moving between SDNN and RMSSD in particular, higher or lower numbers are to be expected.
Do I need to remove my old data?
No. Your history and the switch date are exactly what make the difference understandable.
Sources
- Apple Developer: heartRateVariabilitySDNN
- Apple Support: Manage health data on your iPhone