Circulatory effect of jet noise, with special reference to cerebral circulation

The circulatory effect of jet noise on heart rate, systolic blood pressure and cerebral blood flow was investigated by means of the on-line Doppler ultrasonic technique devised by the author in 20 normal young males, normal elderly males and elderly patients with cerebral vascular disease. The jet noise ranged from 60 dBA to 110 dBA. Heart rate and systolic blood pressure showed slight and transient increase at the level of over 90 dBA. Although the cerebral blood flow was increased at the level of 90--110 dBA, conspicuous dissociation was observed between the vertebral artery and internal carotid artery. The vertebral artery dominant type was more frequent than the internal carotid artery dominant type. Headache and discomfort due to the noise were observed in all the subjects. The above facts suggest that the jet noise induces dysfunction of the autonomic nervous system and various kinds of psychosomatic diseases.