2 doctors weighed in:
Hyperventilation. How fast can someone pass out if hyperventilating?
2 doctors weighed in

Dr. Scott Mackinnon
Anesthesiology
1 doctor agrees
In brief: Varies
This varies from person to person ranging from fast to not being able to fully pass out.
When one hyperventilates, the arterial carbon dioxide level drops, this causes a physiologic decrease in blood flow to the brain, and depending on the person, they may pass out due to decreased blood flow similar to a fainting episode. Don't try this alone or while standing.

In brief: Varies
This varies from person to person ranging from fast to not being able to fully pass out.
When one hyperventilates, the arterial carbon dioxide level drops, this causes a physiologic decrease in blood flow to the brain, and depending on the person, they may pass out due to decreased blood flow similar to a fainting episode. Don't try this alone or while standing.
Dr. Scott Mackinnon
Dr. Scott Mackinnon
Thank
Get help from a real doctor now
Dr. William Forsythe
Board Certified, Emergency Medicine
23 years in practice
171K people helped
Continue
108,000 doctors available
Read more answers from doctors