Because it's the first thing you consider when you go to a heavy-metal concert, we just thought you should know: Head-banging can be hazardous to your health.

That's right — depending on the tempo of the music and the range of motion of your noggin, you could be looking at a head or neck injury, Australian researchers report in today's British Medical Journal.

Andrew McIntosh, an associate professor of biomechanics at the School of Risk and Safety Sciences as the University of New South Wales, and his research assistant, Declan Patton, attended several hard rock and heavy-metal concerts, taking careful note of the most popular head-banging techniques in the audience.

While head-banging generally refers to violent, rhythmic movement of the head, it takes various forms. At the concerts McIntosh and Patton attended, the "up-down" style — which looks like you're bobbing for apples, long hair covering your face at all times — trumped the others. The "circular swing" (long locks swung around your head like a mini tornado) the "full body" (hair whipped up and down in exaggerated fashion) and the "side-to-side" (looks like you're shaking your head in disagreement) didn't get as much representation. (Thanks to our resident head-banging expert, tech editor Larry Greenemeier, for those colorful descriptions.)

After rockin' out with Ozzy Osbourne, Skid Row and Whitesnake, among others, McIntosh and Patton got down to business. Based on the popularity of the up-down style of head-banging at the concerts, and the average tempo of 11 songs deemed the best for head-banging by a minion of local musicians, the scientists developed a mathematical model of how violently you'd have to shake your noodle to hurt yourself. Their conclusion? Head-banging to a song with a tempo of 146 beats per minute can make you dazed and confused (read: give you a headache and make you dizzy) if you're rotating your head by more than 75 degrees.

For the record, popular heavy metal often has a tempo of 180 beats per minute, according to the study. So head-banging to faster tunes with even more range of motion (say, 120 degrees) could cause a neck injury — mainly pain, McIntosh and Patton conclude.

"If the tempo is increased, you have to accelerate more to keep in time," McIntosh tells us. "You've got a limit to that range of motion. The more you're going through it, the higher the risk of mild brain injury or some sort of neck injury."

The tongue-and-cheekiness of the research aside, musicians have actually hurt themselves head-banging. A 15-year-old drummer in his neighborhood band suffered an aneurysm in his cervical vertebral artery, according to a 1991 case report in the journal Pediatric Neurosurgery, and Evanescence guitarist Terry Balsamo had a stroke three years ago that his docs blamed on his head-banging tendencies.

Worried? Try to rotate your neck at no more than 45 degrees. Alternatively, consider slower tempo, easy-listening music instead — or a neck brace, McIntosh and Patton suggest.

"You could have a stylish neck brace built into a leather jacket," McIntosh quips. "We didn’t take into account whether if someone had a poodle-style hairdo, that that might dampen some of the acceleration, or if dreadlocks make it worse. The next step would be to look at the effects of some of these hairstyles."

Rock on!

Image © iStockphoto/Don Bayley