I have pretty good blood oxygen levels, about 92-96%, but when I start to walk around with anything other than sitting, it starts going down sometimes 10 points, and under 90%. What can cause this?

If your oxygen levels drop that much, there is a significant pathology behind it.

Either that or the oximeter is being wonky.

In the country and province I live in, people whose oxygen saturations drop that much with exercise can qualify to recieve supplemental oxygen. Not everybody qualifies for this -- not even everybody with disease problems like emphysema.

YOUR DOCTOR SHOULD KNOW ABOUT THIS.