Does the expression' black out' always mean pass out from drinking? For example, if somebody says ' I blacked out yester', does it always mean drinking too much alchohol to the point where he/she cannot remember anything?
temporary loss of vision and momentary unconsciousness due to diminished circulation to the brain and retina. Blackout refers specifically to a condition which sometimes occurs in aviators resulting from increased acceleration, which causes a decrease in blood supply to the brain cells. The term can also refer to other forms of temporary loss of consciousness and to fainting, as well as to temporary loss of memory and to certain forms of vertigo.