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

Previous studies have shown that exposure to an electromagnetic field (EMF) of 37 Hz at a flux density of 80 mT 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 electro- magnetic 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

INDEXES OF PERCEIVED STRESS AND ANXIETY: AN OBSERVATIONAL STUDY IN NEWLY EVALUATED HYPERTENSIVE PATIENTS

Background. Chronic stress and anxiety are frequently associated with arterial hypertension (Greenage et al, Curr Atheroscler Rep, 2010) and related to sympathetic activation and hypothalamic, hypophyseal and adrenal activation. A link between plasma aldosterone and stress/anxiety has also been recently suggested both in animals and humans, particularly in women (Jezova and Hlavacova, Ann. N.Y.Acad.Sci, 2008). Objective. To investigate in hypertensive subjects the relationships between emotional stress and anxiety with endocrine or hemodynamic parameters as assessed in a routine diagnostic workup for arterial hypertension. Design and Methods. An observational study was started in day-hospital hypertensive patients (n= 74 up to date, 38M, 36F; mean age±SD 53±14), including two questionnaires for self-perceived stress (PSS10) and anxiety (TAS-20)respectively, which were administered on first-evaluation day, soon after (9.00-9:30am) blood pressure and heart rate measurements (by automatic device) and blood samples withdrawal for PRA, aldosterone and cortisol determinations according to standardized procedures. Results. The scores of the two tests were directly related with each other (p <.0001). For both, a positive association was found with heart rate and a negative one with cortisol levels, more significantly (p <.05 and p<0.01 respectively) after the exclusion of cases (n=14) who had positive screening criteria for primary aldosteronism. Anxiety scores were negatively related to cortisol levels particularly in women. No other significant differences or relationships were observed. Conclusions. These preliminary up-to-date results were unable to confirm a significant association between plasma aldosterone and anxiety/stress profiles in hypertensive patients as previously suggested by others. The relationship of anxiety and perceived stress scores with heart rate but not blood pressure levels may be explained by an higher sensitivity of heart rate as an index of sympathetic activation, suggesting it as a sensitive marker of anxiety level in the diagnostic evaluation and follow up of hypertensive patients. Interestingly, in our patients cortisol levels appeared unexpectedly to be negatively related to stress profiles, suggesting a possible primary defect in coping with emotional stress and anxiety in arterial hypertension

Differential magnetic field effects on heart rate and nociception in anosmic pigeons

Several studies have shown that exposure to altered magnetic fields affects nociception by suppressing stress-induced hypoalgesia, and that this effect is reduced or abolished if the treatment is performed in the absence of light. This raises the question as to whether other sources of sensory stimuli may also modulate these magnetic effects. We investigated the possible role of olfaction in the magnetically induced effects on sensitivity to nociceptive stimuli and heart rate (HR) in restraint-stressed homing pigeons exposed to an Earth-strength, irregularly varying (<1 Hz) magnetic field. The magnetic treatment decreased the nociceptive threshold in normally smelling birds and an opposite effect was observed in birds made anosmic by nostril plugging. Conversely, no differential effect of olfactory deprivation was observed on HR, which was reduced by the magnetic treatment both in smelling and anosmic pigeons. The findings highlight an important role of olfactory environmental information in the mediation of magnetic effects on nociception, although the data cannot be interpreted unambiguously because of the lack of an additional control group of olfactory-deprived, non-magnetically exposed pigeons. The differential effects on a pigeon's sensitivity to nociceptive stimulus and HR additionally indicate that the magnetic stimuli affect nociception and the cardiovascular system in different way