title: The effects of intermittent (trapezoidal) noise on man.
abstract: Eight healthy students were exposed to intermittent noise to evaluate the effects of traffic noise on man. The experimental noise exposure conditions were as follows: Exp. 1: Control. Exp. 2: Peak level, 80 dB(A); rise-decay time, 1 sec; duration, 3 sec; and duty cycle 8 sec (on fraction 25%). Exp. 3: Peak level, 75 dB (A); rise-decay time, 500 msec; duration, 4.5 sec; and duty cycle, 8 sec (on fraction 50%). In all experiments, the exposure time was 14 hr. Temporary threshold shift (TTS) growth was followed for 14 hr while saliva cortisol levels were measured for a 24-hr period. Although the coefficient of the regression line of TTS growth recorded in Exp. 1 or Exp. 3 was not statistically significant, the value in Exp. 2 was statistically significant. The circadian rhythm pattern of the saliva cortisol level (during a 24-hr period, mean of 8 examinees) was observed in the three experiments. Essentially, the early morning level of saliva cortisol was high, while the daytime level was relatively low.
mesh_terms: D000328:Adult; D001309:Auditory Threshold; D002940:Circadian Rhythm; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000097:blood; D008297:Male; D009622:Noise; D009624:Noise, Transportation; D012044:Regression Analysis; D012463:Saliva / Q000032:analysis
chemical_list: D006854:Hydrocortisone