Deleting old watches in the Watch removes Health data

during my looking at whatever might have caused the inability to charge during night while sleep mode was on seems to have cleared itself as it just charged to full during sleep - but - during my looking I found that my watch had stopped tracking sleep - lol - sleep causing charging issues turned me on to finding that I had 8 different watches listed as being able to track various activities - seeing that I decided to delete a few to see if it fixed the issue - low and behold it now has two but not the two I wanted - I inadvertently deleted the only other watch ive had with all my past data but it is now tracking sleep again and charging - who new it was smart enough to tell me it had a problem and eventually how to fix it!

Oh, that’s unfortunate. You also just lost all of the Health, fitness, etc., data that those watch sources collected.

Any time you unpair and pair the same watch, you’d think it was the same source, but the Health app creates a new source, even though it’s the same watch. All of that historical data created by your watch while it was that source you deleted is now lost to the Health app.

Some people find issues with the stock watch sleep tracking at times. I use a third-party app to track sleep (AutoSleep) which automatically recognizes sleep based on your movement and heart rate data. It does have a cost (I can’t remember what it was; $4.99 maybe?), but there also exists a free app called Sleep++ which does this well.

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Not meaning to hijack this thread, but I have a few related questions AND observations.

First, can you tell me WHERE you found the Settings that claimed you’d been tracking your activities on 8 DIFFERENT watches?

Second, the issue of “sleep tracking” seems to be a bridge too far for Apple. Last night I went to bed too late (addicted to This Is Us—sometimes I’ll watch 4 episodes after midnight). Still, my Respironics ASV machine (assisted Servo Ventilation—works wonders for people who’s sleep apnea is non-obstructive) accurately tracked my hours of usage and my hours asleep.

This morning when I woke up my iPhone displayed a Health App summary that says I’m spending 8+ hours in bed but getting only 3.2 hours asleep over the last 5 months. There is just SO much wrong with that report! I’m guessing that “in bed” includes lying on a couch watching a riveting movie when I’m not sleeping at ALL, and that the most accurate measure of the hours I sleep comes from Respironic’s 3rd party ASV machine usage tracking app, because that TRULY tracks time in bed and because an external observer (my spouse) will confirm that almost every minute that my puffer mask is ON, I’m OUT!

I’m assuming something feeding information to the “Health” app says time supine is time “in bed” and that something else feeding data to the health app must interpret “no data” nights as “zero hours sleep.” But an app that says you’re reborn or a new watch owner every time you change settings needs some SERIOUS work!!!

Finally, a bit of humor, which I cannot relate without fanning the conspiracy theorists among us. When Marjorie Taylor Green learned that her iPhone was trying to be kind to the environment by concentrating charging activity to low grid power consumption hours, she proclaimed “I’m turning that off! I want to FEED THE TREES.”

By the way, Apple’s “environmentally friendly” charging routines are actually quite sophisticated. For example, they’re invoked ONLY if the GPS sensors say that you’re at home or at your main work address, so if you’re up at 3 am working on that vital presentation for the morning in a hotel somewhere, your charging rates won’t be throttled.

But, bottom line, can someone tell me how to find how many phantom watches I might have supposedly monitoring my activities? And does Apple really know that many routine user actions designed to increase the accuracy with which my watch collects data about me will actually ERASE that very same data?


As I mentioned earlier, any time that you pair a watch to the phone, the Health app creates a new source, as if it is a new watch, even if you have unpaired and then re-paired the same physical watch. You can see the data sources in the Health app - tap your photo icon top-right, tap “devices” from the card that pops up. If you truly have only had one watch and never unpaired it, there will be only one watch source. (You will also see any iPhone that has been logged in to your Apple ID and collected data that is used by the Health app; for example, phones since I think iPhone 6 have been able to count steps, like a pedometer.) I’ve had three Apple Watches that I have paired to three different phone at various times, and unpaired once or twice when I sent the phone in for repair or was having issues with my watch, so I have 20 watch sources from the three different watches.

Under settings on the watch choose health and then devices - I had eight watches and 2 phones - after deleting several of the watches I did lose some of my sleep data and o2 saturation data but my pulse and other data remained - not sure how that actually works but as the previous poster commented - I guess thats appropriate behavior - wish I new what caused the not charging while in sleep issue or if its fixed - I just make sure to put it on the charger before all my devices go to sleep - I use an app called sleep cycle that does a pretty good job of catching snoring and pulse date thru the night - as for the sleep data on the watch - are you seeing any of the data re awake, deep, core and rem sleep? It seems that the watch keeps pretty good data on my sleep patterns that coincide with the other app so not sure what your issues might be with it not working correctly - I just hope I don’t have to pic up the watch and find its at 24% after being on the charger for 3 hours (again)!

I found:
iPhone (1 device)
James’s Apple Watch (2 devices)
JSR Apple Watch 7 (2 devices)
JAR-7 Plus (1 device) - I have NO idea what that is supposed to be

This sounds like something that someone on the Apple Support forums might know something about. I’ll post there, and of course I won’t remove any of them at the moment.

Don’t. Just leave them. If you remove them, any data collected and in the history of the Health app will be deleted and lost.

Did you ever own an iPhone 7+? That sure sounds like what the last phone is.

I think that may be a misunderstanding. From what’s been described on this thread, it sounds like it creates a new database as a part of the pairing process. Which is why when you delete one, you lose the data it contained. But that’s different from claiming that all of these current and historic pairings are still live and being monitored for new values.

Does this imply that upgrading to a new watch and then unpairing one’s old watch will delete all past health data? Or some subset gathered from the old watch? Either way seems to be a loss of critical health data, and not good!!

I’m not quite sure I understand your point. They are listed as devices that are sources of data collection. Delete the source - you delete the historical data they collected. I’m sure they are live, in case, for example, you are somebody with multiple watches who switches between them. (Well, I do have multiple watches. I do occasionally switch.)

Only if you take the steps to delete the source from the health app. It’s pretty hidden; it actually was previously easier to find, and it wasn’t uncommon for people to delete them, not knowing that they’d lose historical data. It was maybe iOS 13 when Apple hid this in the user settings. It used to be accessible in one of the tabs at the bottom of the health app.

There are two different things being discussed and confused here.

The first is the pairing process, where your phone and your watch are configured to know about each other. This establishes a Bluetooth connection (whenever they’re in range) and sets up some iCloud connections (for when the watch connects via Wi-Fi or cellular).

When you retire a watch and disconnect it from your phone, this pairing goes away. When you get a new watch, a new pairing is established.

But then there’s the historic data in the Health app. As has been pointed out, each watch paired with your phone establishes its own store of data (which they are calling a “source”). So if you have used a dozen watches (or have deleted and re-established pairing a dozen times), then you will have a dozen watch-data sources in the Health app. Deleting these will delete the data they contain.

If you un-pair an old watch and then pair a new watch, the new watch will push its health data into a new data store (source). The old data store will remain behind until you manually delete it. Which you shouldn’t do if you want to retain its data.

If you have two watches, then you won’t have removed any pairings. There will be two active Bluetooth pairings - one for each watch.

But we’re (I think) talking about a case where a single watch seems to have lost its (Bluetooth) pairing, and then it was re-created, creating a new data store in the Health app. For this situation, there is only one pairing - the others got lost or deleted, which is why it was necessary to manually create a new pairing for that watch.

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Looking back, no. @lewboski manually unpaired and repaired his watch multiple times to try to fix a battery drain issue, and manually deleted the device(s) from the Health app, inadvertently deleting the wrong device listings.

Really - people should never delete anything from the device listing in the Health app, unless they truly want to start everything from scratch.

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my old series 4 watch was paired many times trying to fix various issues - my new watch (series 8) was only paired once - not unpaired - it was during this charging issue found to not be recording sleep data - it was a mistake to delete devices due to various data loss but - the charging issue and the sleep data issues has been resolved - so cannot claim to know the culprit?