Expiratory Reserve Volume – The amount of air that can be breathed out after normal exhalation

(Pronounced ex-pi-ruh-teree ruh-zerv)

In order to remember what expiratory reserve volume is, it will be necessary to break the words down to their different part meanings as follows:

1. Think of the word ex to mean the beginning of the word exhale. 

Ex = Exhale

Exhale as opposed to inhale. Exhale is breath out.

2. We know that pira means breathing.

Pira = Breathing

3. Reserve is what pilots have as an additional reserve tank and not normally used unless called upon on a long journey. 

4. Reserve volume therefore refers to the additional volume of air.

So if we combine expiratory reserve volume we get:

Exhale, breathing, additional volume of air.

In other words expiratory reserve volume means:

The amount of breath exhaled (out) after normal breathing. 

The normal expiratory reserve volume for an adult male is approximately 1300ml and 700ml for a female, and like inspiratory reserve volume, it is also a measure of the lungs elasticity and ability to expand and contract. Despite forceful exhalation, there will still be a certain amount of air left in the lungs in order to maintain their shape and strength, this is called residual volume.