Ever wondered about the “magnitude and the spatial distribution of low frequency magnetic flux density emissions” from your iPod? Some people have – particularly after a study of one – yes that’s not a typo – ONE person with a pacemaker raised concerns that an iPod could create electromagnetic interference. Because the story was irresistible to the press, the study made headlines around the world.
The Food and Drug Administration decided to investigate, and the peer reviewed results have been published by BioMedical Engineering OnLine. The FDA researchers tested four types of iPod and found that the electromagnetic fields were so localized that they could only be detected within one centimeter of the pod. In other words, the emissions were very weak. The researchers conclude:
The results imply that virtually no low frequency voltages can be induced into the case of an implanted pacemaker or defibrillator through the loop formed by the leads, case, and intervening body tissues. Induced voltages inside the case were undetectable (less than 0.2 mV pp in a 0 – 1 kHz band or less than 2 mV pp in a 0 – 5 MHz band). Data from others indicates voltages of no more than 140 microVolts RMS could be induced in the case and electronics of pacemakers or implanted cardiac defibrillators (ICDs) in the range of 50 Hz to 900 MHz. Based on the miniscule voltages observed in our in-vitro study and others, we conclude that no interference effects can occur in pacemakers exposed to the iPod devices we tested.