Why do some people pass out on roller coasters?

You may have seen the videos of riders on a roller coaster. They will be having fun and screaming, and then suddenly they pass out for a few seconds before regaining consciousness.

This Little Girl Kept Fainting On A Roller Coaster And Her Dad

Is it bad to pass out on a roller coaster? - Quora

Why Do People Faint on Rides? Here Are the Reasons

The Reason Some People Pass Out When Riding A Roller Coaster

We rode all 12 roller-coasters at Six Flags Great Adventure to

Reasons Why Do People Pass Out On The Slingshot Ride - Symboli Mag

10 Surprising Things People Lose on Roller Coasters

Goliath - Review of Six Flags Magic Mountain Coaster

Man in Ohio passes out on a rollercoaster three times

Passed Out On The Roller Coaster at SixFlags!