Acute effects of 50 Hz magnetic field exposure on human visual task and cardiovascular performance

Whittington, Craig; Podd, John; Rapley, B.

doi:10.1002/(sici)1521-186x(1996)17:2<131::aid-bem7>3.0.co;2-4

Cited by 37 publications

(24 citation statements)

References 13 publications

(6 reference statements)

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“…Previous experiments that examined the relationship between exposure to power frequency (50/60 Hz) MF and cognitive performance used circular coils located near the subject's head (Lyskov et al 1993;Podd et al 1995;Whittington et al 1996;Preece et al 1998;Crasson et al 1999), except for the studies Graham et al 1994) in the Midwest Research Institute (MRI, Kansas City, Mo., USA), where rooms surrounded by square coils had been constructed Doynov et al 1999). Compared with coils located near the head, the room surrounded by coils has the disadvantage that performance of the elevation of amplitude of MF is much more limited, but it has the advantage that inside, subjects feel more relaxed during the experiment.…”

Section: Introductionmentioning

confidence: 99%

No influence of short-term exposure to 50-Hz magnetic fields on cognitive performance function in human

Kurokawa

Nitta

Imai

et al. 2003

International Archives of Occupational and Environmental Health

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Section: Introductionmentioning

confidence: 99%

No influence of short-term exposure to 50-Hz magnetic fields on cognitive performance function in human

Kurokawa

Nitta

Imai

et al. 2003

International Archives of Occupational and Environmental Health

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“…The decreased heart rate mentioned above has rarely been replicated in different research laboratories as pointed out by Whittington et al 3) , who found no effect of a 50 Hz, 100 µT magnetic field (of several durations) on heart rate or blood pressure.…”

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confidence: 96%

ECG Changes in Humans Exposed to 50 Hz Magnetic Fields

Borjanovic¹,

Jankovic²,

Pejovic³

2005

Journal of Occupational Health

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ECG Changes in Humans Exposed to 50Hz Magnetic Fields: Srdjan S. BORJANOVIC, et al. Institute of Occupational Health "Dr. Dragomir Karajovic", Serbia and Montenegro-Possible health issues of ELF EMFs include cardiovascular effects since both electrocardiogram and heart-rate changes have been reported in the literature. A non-linear relationship between field strength and biological response has been reported in some studies. In this study, a total of 59 subjects, divided into three independent magnetic field strength groups, were compared. A calculated 12-hour time weighted average (TWA) value of the fields was used as an exposure metric for each of the three locations ("low": 0.067 µT, "medium": 1.18 µT and "high": 5.2 µT) and subsequently used to estimate workers' exposure at these sites. Electrocardiograms were recorded in the resting position. Five parameters were derived from the ECG: heart rate (HR), duration of P wave and QRS wave, and duration of PR and QT intervals. The QT intervals were normalized to a heart rate of 60 (QTc). The obtained data were analyzed first by means of multivariate analysis of covariance and then oneway univariate analyses of covariances (ANCOVA) using exposure duration as a covariate. Only the ANCOVA on the QTc interval was significant. Our results suggest that the relationship between field strength and response is non-linear: the adjusted mean QTc values are similar between the "low" and the "high" group, but significantly lower in the "medium" group. One possible interpretation of our results is that a specific exposure pattern might be responsible for the non-linear effects observed, so that generally, characterizing exposure to electric and magnetic fields using simple metrics such as TWA may be insufficient. Among the possible health effects of exposure to extremely low frequency electromagnetic fields (ELF EMFs), cardiovascular effects have been reported in the database of EMF bioeffects. Studies of ELF EMFs and the cardiovascular system have generally focused on acute rather then long-term effects. Both electrocardiogram (ECG) changes and heart-rate changes have been reported in the literature. An increase in the amplitude of the Twave signal in the rat electrocardiogram was observed during exposure to magnetic fields. This change, however, was the result of a superimposed electrical potential generated by aortic blood flow in the presence of the magnetic field 1) . The T-wave was affected rather than other components of ECG, since blood flows through the aorta during the period when ventricular repolarization is taking place. The increased T-wave voltage was unrelated to the electrical activity of the pacemaker area of the heart and the ECG change was simply a reflection of the coincident "magnetohydrodynamic" voltage generated by the blood flow in the presence of the applied magnetic field.Investigators at one laboratory (Midwest Research Institute, Kansas City, Missouri., USA) have studied the effects of EMFs on the heart rate in humans for several years 1,2...

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“…[11][12][13]15 In addition, in Chiuich and Orekhova's study, subjects were hypertensive, whereas the subjects were normotensive in other studies. [11][12][13][14][15] In our study, subjects with clinically well-defined hypertension were involved; thus, the status of the subjects seems to be important in eliciting an effect of ELF-EMFs on BP. This argument may be supported by our observation that ELF-EMF exposure seemed to have a greater effect on subjects in the ELF-EMF group at the start of the study (for example, during the first week, there were significant differences between the ELF-EMF and sham groups with respect to change in SBP values preand postexposure session), but had a lesser effect as subjects became normotensive (Table 2 and Figure 1).…”

Section: Discussionmentioning

confidence: 83%

“…In Chiuich and Orekhova's study, the subjects were exposed to 10 sessions of ELF-EMF, 16 whereas in other studies, subjects were exposed to only 1 or 2 sessions. [11][12][13]15 In addition, in Chiuich and Orekhova's study, subjects were hypertensive, whereas the subjects were normotensive in other studies. [11][12][13][14][15] In our study, subjects with clinically well-defined hypertension were involved; thus, the status of the subjects seems to be important in eliciting an effect of ELF-EMFs on BP.…”

Section: Discussionmentioning

confidence: 84%

“…8 In several studies, extremely low-frequency (ELF)-EMFs have been shown to have no effect on systolic BP (SBP) or diastolic BP (DBP) in humans. [11][12][13][14][15] However, in a self-controlled study of 60 hypertensive subjects, each of whom was exposed to ten 12-to 15-min sessions of a 50-Hz 30-mT EMF, Chiuich and Orekhova found that the ELF-EMF induced a significant decrease in BP. 16 In that study, posttreatment peripheral vascular resistance was decreased compared with pretreatment, 16 which may have acted to ameliorate hypertension.…”

Section: Introductionmentioning

confidence: 99%

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A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study

et al. 2011

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The effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on blood pressure (BP) are controversial. In this double-blind, randomized, sham-controlled study, we examined the effects of repeated exposure to a 1-lT ELF-EMF on BP in 20 humans with mild-to-moderate hypertension. Subjects were randomly assigned to either the ELF-EMF group or the sham group. Subjects in the ELF-EMF group were exposed to an ELF-EMF (6-and 8 Hz, respectively, peak magnetic field 1 lT, peak electric field 10 V m À1 ) for at least two 10-to 15-min sessions per week, over a period of 4 weeks. In the sham group, the EMF-generating apparatus was not active. We obtained systolic and diastolic BP (SBP and DBP, respectively) measurements at registration and before and after each ELF-EMF exposure session. Subjects in the ELF-EMF and sham groups had mean ages of 52.8 and 55.1 years, and were exposed to a mean of 9.9 and 9.0 sessions, respectively. There was a significant difference between the ELF-EMF and sham groups with respect to change in SBP value between baseline and the end of the exposure regimen (P¼0.02), but not with respect to change in DBP (P¼0.21). There were no adverse events other than mild paresthesia of the hands of two subjects in the ELF-EMF group. Our results suggest that repeated exposure to an ELF-EMF has a BP-lowering effect on humans with mild-to-moderate hypertension.

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Acute effects of 50 Hz magnetic field exposure on human visual task and cardiovascular performance

Cited by 37 publications

References 13 publications

No influence of short-term exposure to 50-Hz magnetic fields on cognitive performance function in human

No influence of short-term exposure to 50-Hz magnetic fields on cognitive performance function in human

ECG Changes in Humans Exposed to 50 Hz Magnetic Fields

A 1-μT extremely low-frequency electromagnetic field vs. sham control for mild-to-moderate hypertension: a double-blind, randomized study

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