Whats the best way to measure SpO2 for someone with COVID? I'm getting different readings on the oximeter. Sometimes it's 95 or 96, but then a minute later it can be 98. When I wake up, it drops to 95 or 97, but if I'm sitting properly, it goes up to 98 or 99. I'm really confused about how to accurately measure SpO2. I also tried doing a 6-minute walk test and within 10 seconds I saw readings from 95 up to 98. Is this normal?