I saw this on an apple forum and wanted to see if this resonates with anyone here. I bought the newest apple watch series 9 and had to return it.
I picked up my watch around 7 pm, and went to sleep with it immediately after buying it. After I woke up the next day (8 hours later), I fainted for the first time in my life. I stayed off of the apple watch for 2 weeks to see if it was anything else health related (saw a bunch of doctors for retina/neurology/primary) and all health visits were fine. I put it on to try it one more time after 2 weeks and within 5 minutes felt dizzy and like I had vertigo.
I reported this to apple but they had a really weird idea that I was using the watch too much which they can monitor by looking at screen time and seemed like a wild guess since I know I barely used it. Posting for awareness to see if anyone else has faced this.
If you think that your Apple Watch make you faint and feel dizzy probably the Apple Watch you make the right decision returning it.