A fear of heights is called acrophobia. Acrophobia can range from fear when on the top floor of a tall building, to fear of standing on a chair. People with acrophobia feel a sense of panic when they're at a certain height and often become unable to trust their sense of balance. Other symptoms can include shaking, dizziness and nausea. That's a pretty extreme reaction to standing on a chair!
Im afraid for heights and the brief was right for me! This is he sensation I feel when I´m in this kind of situations..