[Influence of line frequency electric fields on the heart rate of rats (author's transl)]

At present, the few published research results concerning the effect of 50 HZ fields on biological measurements, for instance on circulatory parameters, show only slight correlation. In order to find objective criteria for the infleunce of a field on heart frequency physically defineable observation conditions must first be created. In the interpretation of the results, it had to be taken into consideration that the measurements were taken immediately after application of the field in both brief and extended exposure. The effect of narcosis during derivation of cardiac activity was also a factor to be considered in this context. Keeping these facts in mind, rats were exposed for up to 50 days to a 50 Hz field with a field-strength of 50 V/m resp. 5300 V/m. Under both field-strength ranges, the heart frequency sank significantly. The intensity and the temporal development of the influence were dependent on the field-strength and the length of application. The comparatively strong frequency drop after 15 min treatment time in the 5300 V/m field points to a stress effect, whose persisting influence determines the development of the biological reaction over a longer period of time. The stronger field is comparable to the value found in the middle of the potential field of a 380 kV high-tension line. For this reason, the experimental results are interesting from the point of view of industrial hygiene as well.