A FIELD-STUDY OF THE EFFECTS OF TRAFFIC NOISE ON HEART-RATE AND CARDIAC-ARRHYTHMIA DURING SLEEP

The aim of this study was to test the hypothesis that traffic noise could increase heart rate, and the frequency or severity of cardiac arrhythmias in susceptible people while asleep. Physiological indicators of sleep, electrocardiograph, and respiration and blood oxygen saturation were monitored continuously overnight in seven elderly men living on a busy road. Continuous recordings of the noise outdoors, at the facade, and indoors in the bedrooms, and video recordings of the traffic were made, simultaneously with the physiological measurements. LAeq, LAmax, LApk, LA90, LA10 and LA1 were measured in each 20 s interval, and noise events exceeding 70 dB(A) outdoors and 50 dB(A) indoors for 2 s or longer were logged. Between 03:00 and 05:00 hours, 65% of the traffic consisted of heavy vehicles. With windows open slightly, indoor and outdoor noise exceeded all local, and internationally recommended criteria for adequate sleep by a wide margin. Cardiac arrhythmia occurred during sleep in four of the men. Heart rate and frequency of cardiac arrhythmia were not correlated with indoor LAeq, LApk or LA1, in stage 2, stage 4 and REM sleep. Two of the four subjects with cardiac arrhythmia showed a significant association (p < 0·05), predominantly in stage 4 sleep, between single indoor noise events and the frequency of cardiac ectopic beats 20-40 s later. © 1994 Academic Press Limited.