Greyout Explained – Theme Park Definition

A greyout (also grey-out) is a physiological state in which a rider experiencing strong sustained positive G-forces temporarily sees a grey or washed-out visual field. The mechanism: positive G-forces pull blood downward toward the extremities, reducing circulation to the eyes and brain. The visual field begins to close in from the periphery and turns grey — the rider remains conscious and in control, but vision is significantly impaired.

Beyond greyout, progressively stronger or longer G-exposure can lead to blackout (vision goes completely dark) or G-LOC (G-Force Induced Loss of Consciousness). Well-engineered coasters keep high-G peaks brief and follow intense sections with recovery elements to prevent greyout build-up.