Standing on a high balcony, looking down from a mountain trail, or walking across a glass bridge can make some people feel perfectly calm. For others, the same experience triggers sweaty palms, a racing heart, shaky legs, or an overwhelming urge to step back.
Psychology says that fear of heights is not necessarily irrational. In fact, a certain amount of caution around heights has likely helped humans survive throughout evolution. When the fear becomes so intense that it interferes with daily life, however, it may be classified as acrophobia, a specific phobia recognized by mental health professionals.
