Is there a way to set an alarm if your oxygen reading is too low ?

Hello janel198,

No, there isn't any setting or feature like that for the Blood Oxygen app on an Apple Watch.

You can take a current reading with these steps:

1. Make sure that your Apple Watch is snug but comfortable on your wrist.

2. Open the Blood Oxygen app on your Apple Watch.

3. Stay still, and make sure your wrist is flat with the Apple Watch facing up.

4. Tap Start, then keep your arm steady for 15 seconds.

5. Wait. The measurement takes 15 seconds. At the end of the measurement, you will receive the results. 

6. Tap Done.

If you have the background readings enabled, you can also find a log of that history in the Health app on your paired iPhone.

1. Open the Health app.

2. Tap the Browse tab, then tap Respiratory > Blood Oxygen.

How to use the Blood Oxygen app on Apple Watch

If you'd like to see Apple add an option for notifications from that application, you can submit that suggestion through their feedback site here: Product Feedback

Cheers!