This is often caused by powerful upward movement. In particular, a strong force in the +z direction (from your head downwards, as shown in Figure 1) will push blood towards your feet and away from your brain. G-force is a measure of acceleration divided by the gravitational constant, g (acceleration due to gravity), and can induce serious physiological effects on the human body. Commonly called “greying out,” this phenomenon is a result of high amounts of G-force acting on your body during high-intensity points of the ride. On certain coasters, it is common for riders to experience a momentary loss of vision and/or consciousness.
There is something enticing about roller coasters: the drop in your stomach as you plummet down a hill, the weightless feeling as you hover at the top of a loop, or the pressing sensation on your head as you fight to maintain consciousness.no, not that last one.
