The effects of low-dosed and high-dosed low-frequency electromagnetic fields on microcirculation and skin temperature...

The purpose of this randomized double-blind cross-over study was to investigate whether a low-dosed pulsed low-frequency magnetic field or a high-dosed pulsed low-frequency magnetic field improves the cutaneous microcirculation and alters the temperature of the foot. Twelve healthy subjects (five women, seven men) aged on average 25.8 years participated in the trial. Based on a randomization list, one of the following three interventions was applied for 30 min through a cushion placed below the non-dominant foot: either a pulsed low-dosed magnetic field (100 uT, basic frequency 30 Hz with a frequency modulation) or a pulsed high-dosed magnetic field (8.4 mT, 10 Hz), or sham treatment. The individual treatment sessions were applied in intervals of one week, at the same time of the day. Cutaneous microcirculation (laser Doppler flowmetry) and temperature (infra-red thermovision) were measured in the dorsum of the foot and the great toe every 5 min during the intervention, and 5 and 10 min post-intervention. With both pulsed low-dosed magnetic field and pulsed high-dosed magnetic field, just as with the sham treatment, a minor drop in temperature and decrease in microcirculation took place. A two-way repeated-measures analysis of variance revealed no significant difference between the interventions for any parameter. It was concluded that a local application of a pulsed low-frequency magnetic field to the foot did not enhance temperature or cutaneous microcirculation in healthy subjects.