Measurements of Lung Volumes

What are my objectives while studying this topic?

By studying this topic you’ll learn how to analyse physiological measurements, such as blood pressure and heart activity.

Why is this important?

Through physiological measurements, fitness and healthcare professionals can measure and monitor the function of the respiratory system. These measurements assist professionals in diagnosing pulmonary disorders as well as improving the fitness performance of an individual or their well being.

Can I get an introduction to this topic?

Yes, why not have a look at the following document:

Preparation of case study evidence relating to treatment of patients

So, let’s get to it: what are physiological measurements of lung volumes?

These measurements refer to measuring the volume of air breathed in and out using a spirometer. By analysing the data, you can interpret information about blood pressure, heart activity, and ECG traces.


An incentive spirometer - used to help patients improve the functioning of their lungs.

What will I be expected to be able to do after studying this topic?

  • Know and describe how to take someone’s blood pressure

  • Be able to analyse and interpret heart pressure data

  • Be able to analyse and interpret ECG traces

  • Be able to evaluate the ethical considerations made in the diagnosis, treatment and monitoring of heart patients

What are the key words to learn and use?

  • Spirometer

  • Inspiratory

  • Capacity

  • Vital capacity

  • Total lung capacity

  • Ventilation rate

  • Asthma

  • Emphysema

How long will this topic take to study?

On average you’ll be looking at about four hours of study time.

What are the main activities on this topic?


Use a spirometer to measure the volume of air you breathe in and out. Be aware of the risks and health and safety procedures involved in using a spirometer. View the following video clip to help you:


Making a homemade spirometer


You could also visit to a university or a football club to discuss correct calibration of instrumentation and examine the degree of error in the equipment used.


View the following clip to learn about the procedure measuring someone’s lung volumes using a spirometer:



Calculate the ventilation rate using the following equation:


Ventilation rate = tidal volume X number of breaths per minute


Analyse, interpret and discuss spirometer traces. Do this by comparing traces to a normal trace and that of a sportsperson.



Find out how exercise affects the ventilation rate, and how this is regulated in response to changing carbon dioxide levels in the blood. You should be able to recognise and describe what these traces show about an individual’s pulmonary function.

Discuss the diagnostic capability of spirometry measurements for pulmonary problems using the analysis of data showing the typical values as given in the specification: ‘Normal values for some physiological measurements', page 15, table 1.


Take peak flow measurements. A nurse could visit to demonstrate peak-flow measurement and discuss the treatment of asthma with clinics and bronchodilator drugs, eg, salbutamol and steroids which reduce the inflammatory response.

Debate the issue of sports people taking steroids to improve their performances, and the effect it has on their breathing. Should ‘self-inflicted’ illnesses be treated? Should a smoker be treated for emphysema? Should expensive treatments be avoided due to cost? Eg, the use of nebulisers for asthmatics.

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