Tips for FEV1 Readings

Forced expiratory volume (FEV1) is the amount of air you can force from your lungs in one second. It is measured using a spirometer. Below are tips for measuring your FEV1.

If your provider has given you other instructions on measuring your FEV1, please make sure you follow them.

• Do not wear tight clothing. It may affect your ability to take deep breaths.
• Sit upright and maintain good posture.
• Before taking the reading, take a few normal breaths.
• When you are ready to take the reading, take a slow, deep breath. Then breathe out as hard as you can for several seconds, until you completely empty your lungs.
• Keep your lips tightly closed (pursed) around the mouthpiece of the device while taking the reading.
• Try not to cough.

© NYU Langone Health. All rights reserved. Reviewed for health literacy. This information is not intended as a substitute for professional medical care. Always follow your health care provider's instructions.