Metal detectors in airports have negative effects on pacemakers and implantable defibrillators. They interfere with their mechanism and can have disastrous consequences. Thus, people with such devices are not allowed to go through these metal detectors in places such as airports, where they are mandatory for the rest.

Metal detectors, however, are easy to avoid. Recent studies have shown that other devices, used almost on a daily basis. One of these devices is the headphones one uses with regular MP3 players, such as the iPod. Headphones have little magnets inside of them that are apparently strong enough to alter the normal heart rhythm kept in place by the pacemakers and defibrillators.

It seems that the MP3 players themselves are virtually harmless and that only the headphones pose a threat to the rhythm regulating devices.

The study show that if the headphones are in one’s ears, the devices are not affected in any way, as the distance between the ears and the heart is big enough for the headphones to not interfere with the functioning of neither pacemaker nor defibrillator.

The distance that allows the headphones to hinder the operation of the devices was estimated at 1.2 inches. Consequently, keeping the headphones in a chest pocket is too close to the heart and is thus life-threatening. The magnets can even completely de-activate internal defibrillators.

However, the magnets do not completely ruin the life-saving devices. Once the headphones are removed from the heart’s vicinity, the devices go back to their optimal efficiency rate. But when it comes to heart rate, a few second are enough for a catastrophe. The headphones seem to be 20 time stronger that the level that affects the pacemakers and defibrillators, and they come from a wide array of big companies, such as Sony or Philips.