There are people who suddenly collapse or twitch without any specific cause when they are stressed, standing for a long time, ...

Fainting or blacking out ... "Some people describe tunnel vision—their vision closing in on them before they actually pass out—and some may actually lose vision but still be aware, not ...

Fainting or blacking out ... “Some people describe tunnel vision – their vision closing in on them before they actually pass out – and some may actually lose vision, but still be aware ...