There's usually a hard and an easy way of discovering things. A Canadian jogger learnt the hard way not to listen to an Apple iPod when running through a thunderstorm.

The 37-year-old man from Vancouver, Canada was jogging while listening to his Apple iPod, when he was struck by lightning. His earphones conducted the electricity through his head, bursting his eardrums and fracturing his jaw. The electricity made his muscles contract and he was thrown over two metres. He also received second-degree burns on his chest and left leg.

His injuries were typical of those sustained from lightening strikes, Dr Eric Heffernan of Vancouver General Hospital, who treated the man, told Reuters .

As human skin has a high resistance, people are surprisingly resistant to the electricity itself. Normally the current passes over the body. However, a conductor - such as sweat or metal, like jewellery or coins in your pocket - will direct the flow of electricity into the skin. This can cause contact burns.

iPod damaged beyond repair

That is what happened to the man's earphones, which "directed the current to and through his head" Heffernan and his colleagues found. The violent contraction of his jaw muscles dislocated and fractured his jaw in four places. That's according to a letter written by the doctors in today's edition of the New England Journal of Medicine .

Two long, thin burn marks extended up his chest and the sides of his face. And there were "substantial" burns inside his ears. The sudden expansion of gases from the hot earphones ruptured his eardrums, and he was deafened. He still suffers from a 50 per cent hearing loss since the accident, which occurred in 2005. The fractures and burns have healed, but the Apple iPod was unsuprisingly damaged beyond repair.

"We couldn't find any reports of similar events [involving headphones] in the medical literature," Heffernan said. He added that there have been reports of a Colorado man being similarly hit when he was listening to music whilst mowing the lawn. A woman was also severely injured in 2006 after being struck while talking on a mobile phone.

"This could have happened with any player, not specifically an Apple iPod," Heffernan pointed out. He said the earphones simply directed the lightning, they did not attract it. "There is no increased risk of being struck by lightning when using an Apple iPod - even if you're listening to heavy metal."