Headbanging to Metallica, Motorhead or Megadeth could be hazardous to your health, according to the British Medical Journal.
Declan Patton and Andrew McIntosh from the School for Risk and Safety Sciences at the University of New South Wales in Sydney, Australia, have studied how heavy metal afficionados jerk their heads to a beat - and the effect it has on their brains.
The Patton and McIntosh research on "headbanging techniques" suggests that thrashing about "like an electro-shocked rabbit" may cause similar effects to whiplash.
The report explains that a typical death-metal rhythm of 146 beats-per-minute or faster, combined with head-banging arcs of at least 45 degrees, will likely cause "mild head and neck injury." Faster tempos and wider arcs could lead to "definite risks of mild traumatic brain injury."
Anecdotal evidence also points to the potential health hazards of thrash rock, the survey says.
"In 2005, doctors believed that Terry Balsamo, the guitarist from Evanescence, experienced a stroke from head banging," the report notes.
The study also used what it calls "the theoretical headbanging model," which measures the all-important beats per minute and the degrees of head arc, to show rebellious cartoon teenager Beavis in little danger of harming himself - but Butt-head could be in real trouble.
Having studied film of the two headbanging to The Ramones' "I Wanna Be Sedated" at 164 beats per minute, the Aussies discovered Beavis' head arc is about 45 degrees, which is below the injury threshold.
Butt-head has a bigger problem. He headbangs with a range of motion of about 75 degrees, which is likely to cause risk of "level one" injuries including painful headaches and dizziness.
Apparently, Butt-head also butts his head much faster than Beavis.
Patton and McIntosh, who attended hard rock and heavy metal concerts in the course of their research, suggest metal fans wear a neck brace while headbanging, or "stick to listening to Michael Bolton, Celine Dion, Enya and Richard Clayderman."