Violently shaking your head to heavy-metal songs can lead to head bleeding so severe that doctors would need to drill a hole in your head to relieve the pain, says an article in the British medical journal The Lancet.
"Some fans might be endangered by indulging in excessive headbanging," says the article by three researchers from the Department of Neurosurgery of Hannover Medical School, in Germany.
Their case report, published Thursday, looked at the woes of a 50-year-old patient who was admitted to hospital in January, 2013, a month after attending a concert by the British band Motörhead.
For two weeks, the man had been in the throes of a constant, worsening headache.
A CT scan showed that he had developped a chronic subdural hematoma, a condition where clotting blood accumulates between the brain's layers of protective lining.
The man had no history of head trauma or substance abuse and didn't have blood-coagulation problems.
The doctors concluded that "headbanging, with its brisk forward and backward acceleration and deceleration forces," caused some of his veins to rupture and bleed inside his head.
To relieve the swelling, the man "underwent burr hole evacuation." In other words, neurosurgeons had to cut a tiny hole into his head to drain out the pooling blood.
The authors – who appear to have some appreciation of the work of Motörhead and its lead singer, Lemmy Kilmister – note that the band was "seminal in the creation of the speed metal sub genre, where tempos greater than 200 bpm are aspired to."
Since it appeared in the early 1970s, headbanging has been generally considered to be harmless but the article nevertheless notes that the practice has been linked to some medical issues.
The problems include whiplash, cracked vertebras, damage to the walls of the carotid artery and chest pains caused by air leaking into the connective tissue around the lungs.
The paper concludes that "this case serves as evidence in support of Motörhead's reputation as one of the most hardcore rock 'n' roll acts on earth, if nothing else because of their contagious speed drive and the hazardous potential for headbanging fans to suffer brain injury."