Blackouts

I've been on quite a few rides where in I've started to black out. Most of the time it happens on helix's such as on Goliath. I am wondering if this is bad for human health?

Has anyone ever had the same experiences?

its been said that the 2 vertical loops on Viper have caused people to get tunnel vision/black out...

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"Ahh Beer. My one weakness. My Achilles heel, if you will" - Homer Simpson
"Whoooa, that's hot. There isn't a man alive who wouldn't get turned on by that. Well, goodbye!" - Homer Simpson

i blacked out my first time on goliath's helix, and i have got tunnel vision numerous times,

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"Ahh Beer. My one weakness. My Achilles heel, if you will" - Homer Simpson
"Whoooa, that's hot. There isn't a man alive who wouldn't get turned on by that. Well, goodbye!" - Homer Simpson

I've blacked out coming out of MF's first turn.

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George Dubya: A Master in the art of "Golfery"
http://www.i-mockery.com/visionary/vacationerchief.asp

I have blacked out/grayed out during the second inversion on Anaconda @ PKD dozens of times!

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Ricochet: Bouncing to you in 2002, Only at King's Dominion!

Batman: The Ride @ Six Flags Over Georgia in the rain. Well, tunnel vision. No black outs.

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Is it fair for a park to charge an additional amount to allow people to bypass normal lines? Yes!

Tense your leg muscles and grunt. It will help to keep the blood in your brain.

Tense your leg muscles and grunt. It will help to keep the blood in your brain.