Fans at heavy metal concerts might want to tone down their enthusiasm just a notch, doctors say, as the common activity known as headbanging can cause brain bleeding and put concertgoers' health at risk.

The exaggerated up-and-down head movements following the beat of the music indulged in by a 50-year-old man attending a concert by Motorhead in Germany left him with a headache that hadn't gone away after two weeks and an eventual diagnosis of a blood clot between his brain and skull, doctors at the Hanover Medical School say.

Following the discovery of the subdural hematoma, surgeons needed to open the patient's skull to remove the clot from the right hemisphere of the brain and allow the brain to drain for six days, they reported in the journal Lancet.

"Our patient had no history of head trauma so we assume that headbanging, with its brisk forward and backward acceleration and deceleration forces, led to rupturing of bridging veins causing hemorrhage into the subdural space," the doctors wrote in their journal article.

The man, whose name was not revealed in the study, recovered fully from the January 2013 incident, they said. He was otherwise healthy, did not have a history of head injuries and denied any drug use, they said.

A survey of the medical literature produced three other reports of subdural hematoma resulting from headbanging, with one of them fatal, they added.

The rapid acceleration and deceleration of brain tissue during headbanging to heavy metal music that is often played at 200 beats per minute can lead to the bursting of tiny blood vessels in the brain, experts say.

And it may be more common than is thought or than has been reported, they say.

"Even though there are only a few documented cases of subdural hematomas, the incidence may be higher because the symptoms of this type of brain injury are often clinically silent or cause only mild headache that resolves spontaneously," Hanover researcher Dr. Ariyan Pirayesh Islamian says.

Despite that, other experts have said, headbangers should feel free to enjoy their concert-going experiences without too much worry about brain bleeding.

"There are probably other higher risk events going on at rock concerts than headbanging," Dr. Colin Shieff, a neurosurgeon and member of the British brain injury advocacy group Headway said. "Most people who go to music festivals and jump up and down while shaking their heads don't end up in the hands of a neurosurgeon."