Next time you walk into a wall of sound thumping through your head and body, and feel like screaming 'you're bursting my ears' at the teenage perpetrator, try this new line: 'You'll break your lungs!' Why? Well, shock value's not a bad start, but there's a better reason. Medical evidence now suggests that very loud music can cause a pneumothorax, a condition where the lining of the lungs spring a leak and part of, or even the whole, lung collapses. According to a paper published in the medical journal Thorax, a journal devoted to chest conditions, there have been five cases of pneumothorax caused by people being too close to speakers thumping out very loud music. Five may not seem a lot but remember, these are the ones we know about. We thought we only had a few cases of Sars until someone went back and checked and found there had been hundreds in Guangzhou already. Most people who come into hospital with this condition get diagnosed as suffering a 'spontaneous pneumothorax' which means 'your lung collapsed and we don't know why'. Asking about recent exposure to loud music isn't one of the usual questions a doctor asks in the middle of this kind of emergency. However, maybe it should be. According to the report, all the cases were people standing next to music speakers when it happened. One of them was a man who was afflicted while driving. According to the report he 'liked to listen to loud music' and his music was certainly loud. He had boosted his stereo system with a 1,000 watt bass box. And that bass was doing its job when suddenly the man developed a severe jabbing pain in his chest and couldn't breathe. Fortunately for both him and the traffic around him, he was able to stop and get to a hospital, where it was discovered his lung had collapsed. The others described in the report suffered their lung collapses while in clubs or concerts. One was standing next to the loudspeakers in a dance club while another was standing next to loud speakers at a rock concert. And there was the heavy metal fan whose lung collapsed while head-banging at a metal concert. Somehow lung-bursters doesn't sound quite the same as head-bangers. All of these 'loud music victims' were young - from 23 to 25. It's not an age at which you expect to suddenly have your lungs collapse. According to the researchers who wrote the article, pressure swings in the atmosphere can change the pressure of air trapped in the bottom of your lungs. Although we all breathe in and out all day, a small amount of gas can stay trapped in air pockets, especially in people with lung damage like smokers. If the pressure in the trapped air rises too rapidly it can make the lung pop: the lung literally springs a leak and collapses. Usually it is only one section that collapses, so the victim can survive long enough to get help. Some are not even aware of how serious their condition is, although they have a lot of chest pain and struggle to breathe. So how does loud music cause these air pressure changes? In the high energy, low frequency range, loud music causes repetitive air pressure changes. So it's no surprise the metal fan suffered an attack.