Jogging to an iPod Tune May Be Dangerous During Thunderstorms

VANCOUVER, British Columbia, July 12 -- Jogging through the woods during a thunderstorm, not a good idea in the first place, can be made still riskier by using an iPod at the same time, reported investigators here.

If lightning strikes, albeit an unlikely event, iPod ear buds can serve as a direct conduit to the head. That was what happened to a 37-year-old man, according to a letter in today's issue of the New England Journal of Medicine.

Eric J. Heffernan, M.B., of Vancouver General Hospital, and colleagues, theorized that the injuries to the patient, which included the rupture of the tympanic membranes in both ears, were caused by a "combination of sweat and metal earphones" that directed current to and through the man's head.

But simply using an iPod, MP3-player, or other earphone devices is unlikely to increase the risk of being struck by lightening, he added.

The man was jogging past a tree at the moment it was hit struck by lightning. Witnesses said the jolt traveled from the tree to the jogger, who was thrown about eight feet.

The man had a number of second-degree burns on his chest and leg, as well as burns on his neck. The burns to his neck and the sides of his face terminated in "substantial burns in external auditory meatus bilaterally, corresponding to the positions of his earphones at the time of the lightning strike."

Tympanic membranes in both ears were ruptured and he sustained a "severe conductive hearing deficit" as well as a mandibular fracture. Computed tomography revealed bilateral dislocation of incudomalleolar joints. Dr. Heffernan said there were no external signs of injury to the jaw, so he speculated that the fracture was caused by muscle contraction.

The most likely explanation for the tympanic membrane fracture was "sudden heating and expansion of air around the current, leading to pressure waves."

Although this may be the first report describing an iPod-related lightning injury, a year ago a letter to BMJ described the case of a 15-year-old girl who was struck by lightning while she was using a cell phone in a large London park during a storm. (See Pocket the Cellphone and Beware the Lightning)