Study type: Medical/biological study (experimental study)

Low frequency therapeutic EMF differently influences experimental muscle pain in female and male subjects. med. app.

Published in: Bioelectromagnetics 2005; 26 (4): 299-304

Aim of study (acc. to author)

To investigate the effects of a low frequency therapeutic magnetic field on subjective pain rating, heart rate, and arterial blood pressure employing experimental muscle pain.

Background/further details

Twelve female and twelve male healthy volunteers participated in this study where each subject served as his/her own control. Muscle pain was induced by intramuscular injection of 5% hypertonic saline into the right erector mucle of the spine.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 100 Hz
Exposure duration: 20 min
pulsating half sine wave

Exposure 1

Main characteristics
Frequency 100 Hz
Type
Exposure duration 20 min
Additional info pulsating half sine wave
Exposure setup
Exposure source
Setup the coil was placed around the body at the L3 vertebral level where the catheter was located
Sham exposure A sham exposure was conducted.
Additional info During the exposure as well as sham exposure, muscle pain was induced by intramuscular injection of hypertonic saline (HS) by an infusion pump connected to the catheter via plastic extension tube. HS was injected into the right erector spinae muscle at the level of L3 spinous process. The muscle pain was induced twice in two separate sessions with at least 2 days interval between them. One session was accompanied by exposure and the other was conducted under sham exposure.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 3.4 mT effective value calculated - at a distance of 30 cm from the coil
magnetic flux density 15 mT effective value unspecified - at the center of the coil
magnetic flux density 6.4 mT effective value calculated - at a distance of 20 cm from the coil
magnetic flux density 1.9 mT effective value calculated - at a distance of 40 cm from the coil

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

Exposure to magnetic field differently affected subjective pain estimates in females and males. Exposure to magnetic field increased averaged pain level and time integral of pain ratings in females, whereas no statistically significant difference was observed in males. Pain related elevation of systolic and diastolic blood pressure was found during both real and sham exposure in both genders.

Study character:

Study funded by