A field study on the immediate effects of exposure to low-altitude flights on heart rate and arrhythmia in patients with cardiac diseases.

Noise from low-altitude military flights differs from most other sources of noise by virtue of its unpredictability in space and time, its very high maximal levels, and the fast increase in noise level at high flight speeds. While this makes low-altitude flights a frightening and annoying experience, the potential immediate health hazards for exposed individuals with preexisting cardiovascular disease are unclear. A field study on the immediate effects of exposure to low-altitude flights on heart rate and arrhythmia was conducted among patients of a rehabilitation clinic for cardiac diseases in the summer of 1990 in Bad Rothenfelde, Germany. Twenty-four hour electrocardiograms of 68 patients taken on days when low-altitude overflights with peak sound pressure levels above 95 dB(A) were registered on the flat roof of the clinic were analyzed for changes in the heart rate or the occurrence of ventricular extrasystoles in four 2-min periods before, around, and after the overflights. Overall, 149 "overflight events" were included in the analysis. No major changes in the heart rate or in the frequency of ventricular extrasystoles were observed, but this could be partly due to problems inherent in the field approach. Nevertheless, the potential effects on heart rate and arrhythmia of low-altitude flights appear to be of limited magnitude compared to the potential effects of other factors, such as psychological or physical exposures, and they are probably too small to be proven under field conditions in an observational epidemiologic study in Germany following the limitations placed on the frequency and altitude of flights in September 1990.