Passing out, too, may cause seizures or even permanent brain damage, though Busis is unaware of any instances of that happening on a roller coaster. “More likely, it's just a transient thing,” he says. “It's just a couple of seconds and you come to and you're fine.” [Read: 10 Ways to Lower Your Risk of Stroke.]

Passing out on a ride—often seen in viral videos of "Slingshot" or high-G attractions—is generally a result of vasovagal syncope or G-LOC (G-force induced Loss Of Consciousness). While the person usually regains consciousness quickly once the forces level out, it is not something to dismiss as entirely "harmless." Fainting indicates that your brain was momentarily deprived of oxygenated blood. If it happens due to "excitement," it’s often a sudden drop in heart rate and blood pressure. However, it can also mask underlying conditions like cardiac arrhythmias, dehydration, or anemia. In 2026, medical professionals advise that if you experience a "blackout" or "greyout" on a ride, you should treat it as a warning sign to stay hydrated and perhaps avoid similar high-intensity triggers until you've confirmed your heart health. Furthermore, passing out while strapped into a moving vehicle carries the secondary risk of physical injury, such as a "whiplash" effect on the neck since the muscles are limp and cannot support the head during sudden maneuvers.