The first effect of noise is anxiety and stress. Noise causes headache by dilating blood vessels of the brain, eye strain by dilating the pupil, etc. It can also cause increase in the rate of heart beat, constriction of blood vessels, decreased heart out put and defective night and colour vision Prolonged and continuous high intensity noise not only causes partial hearing loss but may cause a permanent loss of hearing. A sudden loud noise such as an explosion can damage the tympanic membrane