Baroreflex Sensitivity Correlates with Geomagnetic Activity

Abstract

The objective of this work was to study the influence of geomagnetic activity as reflected by K-indices on the function of arterial baroreceptors. Forty-six experimental runs were carried out in 14 healthy adult male rabbits. Rabbits were sedated by pentobarbital infusion (5 mg/kg/h) and laid on their bellies in a metal drum with their heads fixed during the 50-min experiments. Baroreflex sensitivity (BRS) was estimated after a 15-min resting period by measuring changes in heart rate during nitroprusside-induced decreases and phenylephrine-induced increases in arterial blood pressure. We found a significant negative correlation (R = -0.44) of BRS with actual K-index values that demonstrated impaired sinocarotid baroreceptor functional state and may be one explanation for the increased occurrence of severe cardiovascular events during magnetic storms induced by intense solar activity.