Medical/biological study (observational study)

Alteration of diurnal rhythms of blood pressure and heart rate to workers exposed to radiofrequency electromagnetic fields med./bio.

By: Szmigielski S, Bortkiewicz A, Gadzicka E, Zmyslony M, Kubacki R

Published in: Blood Press Monit 1998; 3 (6): 323-330

Aim of study (acc. to author)

To determine the course of diurnal rhythms of blood pressure and heart rate in a group of workers exposed to various intensities of radiofrequency electromagnetic fields.

Background/further details

For this study 103 healthy men (aged 28 to 50) were selected. 61 men were exposed and 42 men were non-exposed.

Endpoint

effects on the cardiovascular system: blood pressure, heart rate

Exposure

- AM radio transmitters

Exposure	Parameters
Exposure 1: 0.738–1.503 MHz Modulation type: AM Exposure duration: 12 h shift	electric field strength: 200 V/m (to 550 V/m; 23 subjects) electric field strength: 20 V/m (to 180 V/m; 38 subjects)

Exposure 1

Main characteristics

Frequency	0.738–1.503 MHz
Type	electric field magnetic field
Exposure duration	12 h shift

Modulation

Modulation type	AM

Exposure setup

Exposure source	middle-wave radio broadcasting stations
Additional info	103 men aged 28-50 years working at 4 radio broadcasting stations and at 2 radio line stations. All subjects worked in 4 day working cycles with a 12 h day shift, then 24 h rest , a 12 h night shift and 48 h rest. They were 125 shifts per year. 61 subjects from the radio station were considered as exposure group, where as 42 subjects employed at radio line station were considered as unexposed group.

Exposure source

middle-wave radio broadcasting stations

Additional info

103 men aged 28-50 years working at 4 radio broadcasting stations and at 2 radio line stations. All subjects worked in 4 day working cycles with a 12 h day shift, then 24 h rest , a 12 h night shift and 48 h rest. They were 125 shifts per year. 61 subjects from the radio station were considered as exposure group, where as 42 subjects employed at radio line station were considered as unexposed group.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	200 V/m	-	measured	-	to 550 V/m; 23 subjects
electric field strength	20 V/m	-	measured	-	to 180 V/m; 38 subjects

Measurement and calculation details

A broadband MEH-1a meter with AE-1 and AE-2 probes for electric field and AH-1 probe for magnetic field was used for measurements. Maximum daily exposure levels were established for each subject at separate sites on the basis of partial (6 min) doses recorded during performance of routine tasks by a particular groups of workers during the 12 h shift.

Reference articles

Bortkiewicz A et al. (1995): Dysregulation of autonomic control of cardiac function in workers at AM broadcasting stations (0.738 - 1.503 MHz)

Exposed system:

human
whole body

Methods Endpoint/measurement parameters/methodology

effects on the cardiovascular system: blood pressure, heart rate (oscillometry, 24 hours ambulatory blood pressure measurement)

Investigated system:

investigation on living organism

Investigated organ system:

cardiovascular system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The subjects of the control group exhibited typical, well-preserved diurnal rhythms of blood pressure and heart rate with two maxima (at about 14:00 and 17:00-18:00 h) and one minimum (at about 2:00-4:00 h).
For workers exposed to radiofrequency electromagnetic field a significant lowering of the amplitudes of rhythms of blood pressure and heart rate and a shift of the acrophase to an earlier time (11:00-12:00 h) were observed. These changes were more pronounced among workers exposed to high intensities of radiofrequency electromagnetic field.
The clinical relevance of the present finding needs to be investigated in further studies.

Study character:

medical/biological study
observational study
full/main study

Study funded by

European Union (EU)/European Commission
National Committee for Scientific Research (KBN), Poland

Suresh S et al. (2011): Cell-Phone Use and Self-Reported Hypertension: National Health Interview Survey 2008
Israel M et al. (2007): Cardiovascular risk under electromagnetic exposure
Vangelova K et al. (2006): Cardiovascular risk in operators under radiofrequency electromagnetic radiation
Mitsutake G et al. (2004): Does exposure to an artificial ULF magnetic field affect blood pressure, heart rate variability and mood?
Krewski D et al. (2001): Potential health risks of radiofrequency fields from wireless telecommunication devices
Bortkiewicz A et al. (1997): Ambulatory ECG monitoring in workers exposed to electromagnetic fields
Jauchem JR (1997): Exposure to extremely-low-frequency electromagnetic fields and radiofrequency radiation: cardiovascular effects in humans
Bortkiewicz A et al. (1996): Heart rate variability in workers exposed to medium-frequency electromagnetic fields
Bortkiewicz A et al. (1996): [Evaluation of selected parameters of circulatory system function in various occupational groups exposed to high frequency electromagnetic fields. II. Electrocardiographic changes]
Zmyslony M et al. (1996): [Evaluation of selected parameters of circulatory system function in various occupational groups of workers exposed to high frequency electromagnetic fields]
Bortkiewicz A et al. (1995): Dysregulation of autonomic control of cardiac function in workers at AM broadcasting stations (0.738 - 1.503 MHz)