Human head exposure to a 37 Hz electromagnetic field: Effects on blood pressure, somatosensory perception, and related parameters

Abstract

Previous studies have shown that exposure to an electromagnetic field (EMF) of 37 Hz at a flux density of 80 microT peak enhances nociceptive sensitivity in mice. Here we examined the effects on pain sensitivity and some indexes of cardiovascular regulation mechanisms in humans by measuring electrical cutaneous thresholds, arterial blood pressure, heart rate and its variability, and stress hormones. Pain and tolerance thresholds remained unchanged after sham exposure but significantly decreased after electromagnetic exposure. Systolic blood pressure was significantly higher during electromagnetic exposure and heart rate significantly decreased, both during sham and electromagnetic exposure, while the high frequency (150-400 mHz) component of heart rate variability, which is an index of parasympathetic activity, increased as expected during sham exposure but remained unchanged during electromagnetic exposure. Cortisol significantly decreased during sham exposure only. These results show that exposure to an EMF of 37 Hz also alters pain sensitivity in humans and suggest that these effects may be associated with abnormalities in cardiovascular regulation.

A literature review: the cardiovascular effects of exposure to extremely low frequency electromagnetic fields

“…Using a 50 Hz Weld with Xux densities of either 40 or 80 T for 90 min of exposure, Ghione et al (2005) found no eVect on blood pressure or HR. These results were in agreement with their earlier results demonstrating that a 37 Hz, 80 T exposure did not result in alterations of cardiac rhythm (Ghione et al 2004). In a shift of research focus, Sait et al (2006) designed a study that provoked controlled changes in the sympathetic-parasympathetic balance in order to determine if there were any subtle Weld related changes.…”

“…The contrasting results between the two studies ( Table 2) by Ghione et al (2004Ghione et al ( , 2005 might be explained by the drawing of a 20 ml blood sample prior to exposure in the Wrst study, which was not done in the second one. Graham et al have previously reported that physiological arousal associated with blood sampling was likely responsible for the eVects on HRV they observed in some of their studies .…”

“…In a subsequent study, Ghione et al subjected ten male volunteers to a head only, 37 Hz EMF at a Xux density of 80 T for 60 min. They reported a signiWcant increase in systolic blood pressure during Weld exposure, but no eVects on HR during the same period (Ghione et al 2004). In 2005, Ghione et al investigated the eVects of head only exposure to a 50 Hz Weld with a magnetic Xux density of either 40 or 80 T for 90 min in human male subjects, speciWcally examining pain perception, electrocephalographic (EEG) eVects, and cardiovascular parameters including HR and blood pressure.…”

“…Graham et al have previously reported that physiological arousal associated with blood sampling was likely responsible for the eVects on HRV they observed in some of their studies . In addition, the studies by Ghione et al (2004Ghione et al ( , 2005 were conducted at diVerent frequencies, raising the possibility of a "window frequency eVect". The study by Korpinen and Partanen (1996) was conducted outdoors, which makes controlling for the eVects of other confounding variables or modifying factors diYcult.…”

The response of the human circulatory system to an acute 200-μT, 60-Hz magnetic field exposure

“…In contrast, Ghione and colleagues exposed 10 volunteers for 60 min to a head only, 37-Hz MF at a flux density of 80 lT. They observed a significant increase in systolic blood pressure during MF exposure; however, no HR effects were seen during this same time frame (Ghione et al 2004). In a subsequent study, the same authors examined the effects of head only exposure for 90 min to a 50-Hz field with a flux density of either 40 or 80 lT. No MF exposure effects were observed for HR or blood pressure in either of the exposure groups (Ghione et al 2005).…”