Does COPD cause 90 reading blood O2 levels?Does this cause rapid pulse?

Hello. Thank you for posting.

Oxygen saturation is a measure of how much oxygen the blood is carrying through the body. Oxygen attaches to the hemoglobin molecules in the blood. The oxygen carried in the blood is usually referenced as a percentage of the maximum amount of O2 the blood can carry.
Normal oxygen saturation levels range from 95 to 100 percent. Oxygen levels under 90 percent are considered low and are also known as hypoxemia. Oxygen saturation is also referred to as SpO2. If the saturation drops below 90%, a variety of symptoms may begin to occur such as increased shortness of breath with activity, increased heart work (reflected by an increase in pulse rate), the presence of bluish lips or nail beds, headaches, clumsiness, and confusion.

Helena