john smith writes:

Negative G's are what you do while flying aerobatic outside maneuvers.
They can make your eyes all red.

They can also cause retinal damage and hemorrhagic CVAs. Quite a risk
to take for a brief thrill. It's much safer to pass out briefly with
positive Gs, which typically has no sequelae. (Of course, if you're
flying, you'll want to avoid this, too.)

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