@srasnick98 It is normal for pulse ox readings to bounce around a little bit. Think about it. You are not constantly inhaling air; there is a rhythm of exhaling and inhaling and oxygen needs to be absorbed when air is inside the lungs. If there is greater need for oxygen, your body signals to increase the rate of breathing such as when exercising, or walking, etc. Your body needs and uses oxygen at different rates depending on what you are doing and your heart and lungs make adjustments accordingly. What the pulse ox is actually measuring is the color of your blood in your finger because oxygenated blood is red, and de-oxygenated blood in the veins is bluish in color. It does this by shining a light through your finger. If a person is lethargic and has a low reading for pulse ox that is different. Try playing with it by inhaling deeply and holding your breath and see if you can increase the numbers. Allergies and phlegm do affect these readings by interfering a bit with oxygen absorption and that is normal too. You can always put a new battery in if you are concerned about accuracy. I always know by how alert I am where my oxygen readings would be and I would only measure it if I was getting tired or having difficulty breathing.