How to measure someone's oxygen levels?

Measuring someone’s oxygen levels is like checking how full their lungs are after taking a big breath.

Imagine you have a balloon that fills up when you blow into it. Your lungs work the same way, they fill with air, and part of that air is oxygen, which your body needs to stay healthy. To check how much oxygen someone has, we use a special tool called a pulse oximeter.

A pulse oximeter looks like a little clip you put on your finger or toe. It shines light through your skin and measures how much of that light is absorbed by the blood, which tells us how much oxygen is in there!

It’s kind of like having a tiny helper inside your finger that counts how many oxygen bubbles are floating in your blood.

The tool gives a number, usually between 90 and 100. A higher number means more oxygen, like having a full balloon instead of one that's just partly filled. If the number is low, it might mean the person needs to take deeper breaths or get extra help with their lungs.

Sometimes doctors use bigger machines to check oxygen levels too, but the little clip on your finger is quick and easy, like checking if a toy car has enough batteries to keep going!