My fathers O2 levels even when up and moving are normally in the mid 90's. The last 2 days they have been fluctuating from the mid 90's to the upper 80's. This is the 1st time his O2 level has ever dropped below 90. Also, he has been very tired and weak the past few days. So my question would be do levels fluctuate like this? Could it be possible that he may be getting walking pneumonia?