
Peak flow diary
Peer reviewed by Prof Cathy Jackson, MRCGPLast updated by Dr Colin Tidy, MRCGPLast updated 5 Jan 2018
Meets Patient’s editorial guidelines
- DownloadDownload
- Share
- Language
- Discussion
- Audio Version
- Add to preferred sources on Google
This leaflet is designed to be printed out for people to record their peak flow reading.
Peak flow diary for printing off

To take a peak flow reading
Put the marker to zero.
Take a deep breath.
Seal your lips around the mouthpiece.
Blow as hard and as fast as you can into the device.
Note the reading.
Repeat three times.
The 'best of the three' is the reading to record on the chart.
What are normal and abnormal peak flow readings?
Normal peak flow readings vary, depending on your age, size, and sex. The range of normal peak flow readings is published on a chart, and doctors and nurses refer to the chart when they check your peak flow reading. In healthy people, peak flow readings vary slightly from time to time. The reading is often slightly higher in the evening compared with the morning.
Peak flow normal values

Below is an example of a two-week diary of peak flow readings done by a child who has quite bad asthma.
Peak flow graph

Patient picks for Asthma

Chest and lungs
Why your favourite perfume could trigger an asthma attack
Almost half of 5.4 million asthma sufferers in the UK find that perfume triggers their symptoms. We investigate why this is and what can be done to manage its effects.
by Ginny Weeks

Chest and lungs
What happens during an asthma attack?
Asthma is a common condition that affects the smaller airways (bronchioles). From time to time the airways narrow in people who have asthma. The typical symptoms are wheeze, cough, chest tightness, and shortness of breath. The extent of the narrowing, and how long each episode lasts, can vary greatly.
by Dr Laurence Knott
About the authorView full bio

Dr Colin Tidy, MRCGP
General Practitioner, Medical Author
MBBS, MRCGP, MRCP (Paediatrics), DCH
Dr Colin Tidy is an NHS Doctor, based in Oxfordshire.
About the reviewerView full bio

Prof Cathy Jackson, MRCGP
Medical Author
BSc (Hons) Physiology, MB, ChB, MRCGP, MD
Professor Cathy Jackson graduated from Manchester Medical School having gained a first-class honours degree in physiology along the way.
Article history
The information on this page is peer reviewed by qualified clinicians.
Article also available in English, German, Spanish, French, Italian, Portuguese, Hindi, Hebrew, Arabic, and Swedish.
5 Jan 2018 | Latest version
Join the conversation
Share your thoughts or experiences with others in our patient communities.

Ask, share, connect.
Browse discussions, ask questions, and share experiences across hundreds of health topics.

Feeling unwell?
Assess your symptoms online for free
Sign up to the Patient newsletter
Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.
By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.
More in chest and lungs
- Air pollution blamed for a third of new asthma cases in Europe
- Can you really 'grow out' of asthma?
- Chest and lungs videos
- Common asthma inhaler mistakes to avoid
- How to avoid catching a cold on public transport
- How to cope with asthma in the summer
- How to handle asthma during the winter months
- Is it indigestion or a heart attack?
- Is it whooping cough or just a cold?
- Is your cough really a chest infection?
- Managing hay fever and asthma: tips to survive pollen season
- Should parents worry about 'dry drowning'?
- The warning signs of a heart attack in women
- What happens during an asthma attack?
- What is walking pneumonia?
- What should you do if your child is wheezing?
- What you need to know about pneumonia
- What's the difference between double pneumonia and pneumonia?
- When to worry about a persistent cough
- Why your favourite perfume could trigger an asthma attack
