What happens in a breathing test?

• When you breathe, air goes into your nose and mouth, down the tube to your lungs. You have two lungs inside your chest.

• Air contains a gas that the body needs to work, called oxygen (said: ock-see-jen). Your body takes the oxygen from the air and moves it into your blood cells.

• Blood carries oxygen and goodness to every part of your body. Your body needs oxygen to work.

• We would like to see how well your lungs are working. This is called a lung function test. When you get to the unit, we will ask you lots of questions about your breathing.

• Next we will measure how tall you are and what you weigh. After this, you will start the lung function test. You may have one test during the visit or lots of different ones.

• One test is a blowing test. We will ask you to blow as fast and hard as you can for as long as you can into a plastic tube. You could think about blowing out candles or popping balloons.

• If you are going on holiday, you will have a 'fitness to fly' test. You will need to sit in a plastic cabin that looks a bit like a phone box.

• We will put a clip on your finger. This measures how much oxygen is in your blood through your skin.

• Another test involves taking a big breath, holding it for about 10 seconds and then breathing out again.

• The doctors will look at the results and explain them to you.

• Please ask if you have any questions.