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dragonweaver
User level: Level 1 (8 points)

Blood Oxygen and iOS 27.01

After updating to iOS 27.01, my Blood Oxygen from my watch is no longer working. It looks like it's taking the blood oxygen on my watch, but when I look for the data point on my phone, health app, it's not there. When I dig into the data, under settings, it says "not able to analyze". iPhone 16, iOS 27.01, Apple Watch Series 6, watchOS 26.6. I've restarted both my phone and my watch, but it didn't help.

Posted on Oct 22, 2026 2:27 PM

3 replies

WheelieNick
User level: Level 9 (74,110 points)

Oct 23, 2026 6:06 AM in response to dragonweaver

Hi there


Please try this


    • On your Apple Watch, go to Settings > Passcode and make sure Wrist Detection is turned on. If it is already on, toggle it off, restart the watch, and turn it back on. 
  • Run a Heart Rate or ECG Check:
    • Open the ECG app or take a manual heart rate reading on your Apple Watch first, then try running the Blood Oxygen app again. This often forces the sensor and background health services to handshake properly. 
  • Verify iPhone Health Settings:
    • Open the Watch app on your iPhone, tap Blood Oxygen, and ensure that blood oxygen measurements are enabled and properly synced. 
  • Check Connectivity and Airplane Mode:
    • Make sure Bluetooth and Wi-Fi are enabled on both devices, and that Airplane Mode is turned off so the watch can relay measurement data to your iPhone for analysis.
  • Reinstall or Re-enable the Blood Oxygen App:
    • If the app was uninstalled or disabled during a previous software quirk, check the App Store on your Apple Watch or re-enable it via the Watch app on your iPhone. 


dragonweaver Author
User level: Level 1 (8 points)

Oct 23, 2026 6:50 AM in response to WheelieNick

Thank you! I tried everything, one by one. I had to remove and reinstall the blood oxygen app on my watch to restore function.

Kilgore-Trout
User level: Level 8 (43,363 points)

Oct 23, 2026 6:31 AM in response to dragonweaver

You might also try simply cleaning the bottom side of the watch to ensure nothing is interfering with the sensors.


It also isn’t that unusual for this to occur. Several factors can impact the reading and throw it off. Like most of the data that the watch gathers, it uses indirect measures that can easily be thrown off.

Originally posted at discussions.apple.com/thread/256381141