I have acrophobia, or a very irrational fear of heights. 
There's nothing irrational about falling to your death.
Well, the thing about acrophobia is that you can feel that immense fear, even when you aren't particularly high up. 
So even if you're just standing on top of something short like a stepladder?
or climbing in mountainous terrain and also in certain jobs such as steeplejacks or wind turbine mechanics. Some people may also be afraid of the high wind, as an addition of falling. This is actually known as added ancraophobia.
People with acrophobia can experience a panic attack in high places and become too agitated to get themselves down safely. Approximately 2–5% of the general population has acrophobia, with twice as many women affected as men. The term is from the , "ákron", meaning "peak, summit,
Acrophobia
Acrophobia is an extreme or irrational fear or phobia of heights, especially when one is not particularly high up. It belongs to a category of specific phobias, called space and motion discomfort, that share both similar causes and options for treatment.
Most people experience a degree of natural fear when exposed to heights, known as the fear of falling. On the other hand, those who have little fear of such exposure are said to have a head for heights. A head for heights is advantageous for those hiking