Geomagnetic Disturbances and Cosmic Ray Variations in Relation to Human Cardio-health State: A Wide Collaboration

Research groups from Athens (Greece), Baku (Azerbaijan) and Sofia (Bulgaria) carry out relevant helio-biological and bio-meteorological studies and the obtained results reveal that human organism is sensitive to changes in environmental physical activity and reacts to these changes through variations of human body's physiological parameters such as systolic and diastolic blood pressure, heart rate (HR), human brain's bio-electrical activity, etc. Results of a collaborative study conducted by these scientific groups concerning the influence that geomagnetic disturbances and cosmic ray activity might have on human cardio-health state, are described in this paper. This multi-disciplinary study refers to the time period of 15 July 2006 - 31 March 2008. Daily HR data, which were digitally registered for seven functionally healthy persons on working days and Saturdays in the Laboratory of Heliobiology, located at the Medical Center INAM, Baku, Azerbaijan, were studied in relation to daily variations of cosmic ray intensity (CRI), measured in the Neutron Monitor Station of the University of Athens, Greece, and daily variations of Dst and Ap geomagnetic indices taken from accessible data sources. The time interval from 4 to 22 December 2006 was most interesting as it was characterized by extreme solar and geomagnetic activity (GMA) and intense cosmic ray events such as a series of Forbush decreases which started on 6 December 2006 and lasted until the end of the month, and a solar proton event causing a Ground Level Enhancement of the CRI on 13 December 2006. A sudden decrease of the CRI on 15 December resulted in a major geomagnetic storm, which was recorded also in Athens Station (cut-off rigidity 8.53 GV) with amplitude of 5%. The statistical methods were applied to establish a statistical significance of the effect of GMA levels and CRI variations on HR (for the whole group and for each person in the group). Our study has revealed that HR variations can be connected to geomagnetic disturbances and CRI variations. The effects of HR increase were more pronounced for high levels of GMA (when geomagnetic storms occur) and large CRI decreases. HR increased on the days before, during and after geomagnetic storms with high intensities and on the days preceding, and following CRI decreases. (authors)