Pulse Oximeter how accurate is on F6x?

1. Same

6-7 breaths per minute seems worthy of a medical check.   My pulse ox is normally in the 93-98% range.  My BPM is 13-17.  I'm 54 and run ultra marathons with a RHR of 42 with dips into the high 30's. 

I can't speak to how accurate it is for any given watch or individual though. A cheap second opinion is a fingertip reader, they look to cost anywhere from $12 to $30 on amazon. 

The ups and downs could be a sign of sleep apnea, it's pretty common. 

How old is he?

>65

To the question of accuracy :

This is not a medical dispositive.

About absolutes values measurement :

    Life conditions are considered to be compromised below 90.... under 85, that's a critical situation.

    So indeed, the value 80 is absolutely not realistic, and can be fully discarded as such.

With that said, about relatives values :

   The device is so imprecise (get at your doctor, get a read with a real medical device, you'll see what I mean :) ), that small changes, can be discarded, and can't really be used.

But, here, comparing 100% of saturations sometimes with 80% , is another story.

It is a strong indicator, that something is going wrong :

- The device is moving during the night, due to a specific position , or stuck not touching the wrist, due to the joints position.

- apnea problem

- very low cardiac frequency, due to another problem.

So now about apnea more specificaly, there is common symptoms, often there :

- frequent needs to go to the bathroom (2/3 times a night), even without drinking a lot of waters, most of the nights

- feeling to be tired in the morning

- memory loss

So as you can see, nothing is evident, and jumping in the face, no real reason to worry, but it could be intesting to get advices of a real profesionnal :-)

Hope this clarify a bit :)