Speed heavy metal band Motörhead is so hardcore, headbanging to them could literally make your brain bleed, according to a new case study published today in The Lancet.

The unsurprising findings (whipping your skull to and fro for hours on end might not be good for you) from the surprisingly entertaining study, detailed the case of an anonymous 50-year-old man who came into Germany’s Hannover Medical School with complaints of a two-week constant headache. A CT scan showed the man suffered from bleeding—medically known as chronic subdural haematoma—on the right side of his brain.

He didn’t use drugs and had no medical history that might explain the pain. But he did tell doctors that he had been to a Motörhead show in the last month and had, as heavy metal fans are wont to do, banged his head.

Surgeons drilled a small hole in his skull and removed the blood clot. His headache cured, the man went home and two months later, he was given a clean bill of health.

Doctors wrote in the study, that “headbanging, with its brisk forward and backward acceleration and deceleration forces, led to rupturing of bridging veins causing haemorrhage…” and declared that the 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.”

Despite the verdict, Motörhead isn’t the only band that can inspire dangerous moves. And it’s not the first time the medical profession has asked metal heads to take care, saying it can cause injuries from whiplash to tears in the carotid artery—basically “shaken metalhead syndrome.” As the study’s author noted, there have been at least three other cases of brain bleeding from headbanging, including one acute case which led to the patient’s sudden death.

Even Slayer frontman Tom Araya announced in 2010 he was retiring his signature helicopter and figure-eight style thrashing. Doctors had implanted a steel plate into his spine to deal with the physical damage, “from 30 years of being in the same position, headbanging,” Araya said.

While Hannover Medical School’s doctors stopped short of making recommendations to other headbangers, researchers at The University of New South Wales (UNSW) have the prescription covered. They warned eager headbangers in 2008 that trashing in a range larger than 75 degrees to songs with a tempo of 146 bpm can elevate risk of headaches and even strokes. They suggested rockers might mitigate the danger with some very un-metal suggestions: like switching to lighter “adult oriented” rock, changing their style by thrashing only to every second beat, or wearing a neck brace.