Giddiness occurs when we lose our sense of balance. The sensations perceived by the eye, inner ear, skin, muscles and joints help the body to know its stability. Several unusual situations, such as travelling in a bus or looking down from a great height, over stimulate and confuse that part of the brain which controls balancing. (This is very close to the part which induces vomiting). When we look down from a great height, abnormal visual signs transmitted to the brain, without any corresponding information from other parts of the body. Likewise, while looking out in a fixed direction while travelling in a bus, the eye sends fast changing visual signals to the brain. Such signals confuse the mechanism in the brain and lead to giddiness and vomiting.
