Defensive activation toward noise

Long lasting sounds cause physiological reactions referred to as “ergotropic”, “orienting” or “defensive” reactions, the components of which have been demonstrated in laboratory experiments. In a study of residents exposed to aircraft noise in Germany, about 400 subjects were given white noise exposure of 85 and 100 dB in the laboratory. About 70% demonstrated vasoconstriction at the finger tips and temple, increase in muscle activity, initial deceleration of the heart rate and increase in tracking error and bodily movements. The number and degree of these reactions to laboratory noise increase with the number and loudness of aircraft movements at the homes of the subjects.