Three minute step test (3MST)

You will receive a letter or message through MyGOSH in advance of the test, giving you more information on the test.

Please make sure that your child wears suitable clothing and shoes for performing the exercise test.

If your child uses supplemental oxygen (continuously or sometimes during the day), please bring this with you.

Your child should continue to take their regular medication as usual.

The person accompanying your child for the test should have ‘Parental Responsibility’ for them.

Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.

On the day of the test your child will be greeted by a physiologist. They will start by explaining the 3MST and you will have the opportunity to ask any questions.

We will put a pulse oximeter on your child's finger or forehead to measure oxygen saturations and heart rate during the test. We will ask your child about their breathing and leg tiredness using a simple scoring scale called a visual analogue scoring system.

The physiologist will ask your child to step on and off a step to a metronome beat. The test is timed at three minutes but if your child is unable to complete this or keep with the rhythm of the metronome, the test may be stopped early. This test can be challenging for some so lots of encouragement will be given throughout.

Please note, some children - including younger children around six years and under - may not be able to perform the test due to co-ordination of stepping to the beat.

Once the test has stopped, your child will be asked to score their breathing and leg tiredness on the scoring system again.

Your child will be allowed to rest for as long as they need after the test.

The test results will be uploaded onto our electronic patient record system for your doctor to view. If you are seeing your doctor in clinic or later that day, they will go through the results with you.

If you are not seeing the doctor that day, they will still be able to view your test results and contact you if there is anything your child needs to do before their next appointment.

If you need any further advice or information about the 3MST you can contact the Lung Function Unit on 020 7405 9200 ext 5456 or via the MyGOSH portal once you have registered.