Final answer:
Mild hypoxemia increases heart rate (HR) due to the body's response to low levels of oxygen. This is known as tachycardia.
Step-by-step explanation:
Mild hypoxemia, which is a low level of oxygen in the blood, can lead to an increase in heart rate (HR). When the body is not getting enough oxygen, the heart responds by pumping faster to deliver oxygen to the tissues. This is known as tachycardia. So, in answer to your question, mild hypoxemia increases HR.