Initially I found the Blood Oxygen monitor to be a godsend on my Apple Watch at the start of covid, but over time, a short period of time, I found myself relying on it less and less.
With a Blood Oxygen monitor in the house (they are only £15, please buy one) I had the opportunity to compare the two and the differences were stark. On the whole the Apple Watch solution underscored my results to the point that a 92 on my dedicated monitor would give 89 on the watch. 94 on the monitor would bring in 92 on the watch and so on. Add to this the fact that within a minute my results could vary from 89 to 96 and it felt like a lottery as to what would come back.
I was also concerned that the watch is on my left wrist, but that the dedicated monitor is used on the right finger (a true extremity) and so surely there is an obvious advantage to the monitor because it is at the end of what it needs to test.
And finally, while having my observations measured in the hospital, on a proper device that checked pulse and blood pressure etc, I checked on the Apple Watch and I measured 96 on the hospital equipment and 93 on the Apple Watch. The doctor doing the obs said that he had seen this before and that he also owned an Apple Watch. He was quite confident in the heartrate monitor and even the ECG, but he felt that the Blood Oxygen sensor was off from the first time he tried it.
The good news is that it does seem to offer lower scores than reality, the opposite could cause real problems with people thinking they are well when they are not, but it could lead to some visiting hospitals when they simply don’t need to. And that is dangerous in the current climate.