Three Minute Step test

This page from Great Ormond Street Hospital (GOSH) describes what to expect when your child is booked for a 3MST test. The three minute step test (3MST) is performed in the lung function unit, and can be used to assess your child’s exercise tolerance.

What to bring with you

A letter or a MyGosh message will be sent in advance to give you the relevant information prior to the day of testing. Please ensure 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. Patients should continue the use of regular medication.

Important information

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.

What happens on the day

On the day of the test your child will be greeted by a physiologist, they will start by giving a description of the test and you will have the opportunity to ask any questions. For monitoring during the test a pulse oximeter is placed on your child's finger or forehead to measure oxygen saturations and heart rate. We will ask your child about their breathing and leg tiredness using a visual analogue scoring system – this is a simple scale to use.

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, children of a younger age (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 complete the visual analogue score again.

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

Getting the results

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.

Further information

If you need any further advice or information about the Three Minute Step Test you can contact the Lung Function Unit on 020 7405 9200 ext 5456 or via the MyGosh portal once you have registered. 

Compiled by:
The Lung Function Unit in collaboration with the Child and Family Information Group
Last review date:
May 2024
Ref:
2020F2308