 If you search for heavy metal in the National Library of Medicine database, most of what you find is on heavy metal contamination in fish, for example, making it so hard to clearly establish the role of fish in a healthy diet, perhaps helping to explain the quintupling of odds of autoimmune diseases like juvenile arthritis, for instance. But searching the hazards of heavy metal also pops up entries like this on the risks from heavy metal music. Here they were talking about traumatic injuries from slamming around, but you're more likely to get injured at an alternative rock concert. It's the Goo Goo Dolls you've got to worry about, not 9-inch nails. Okay, sure, music-induced hearing loss is a serious problem, but that can be from any loud music. It's interesting, clinical recommendations include the 80 to 90 rule. No more than 80% of the maximum volume on personal listening devices for no more than 90 minutes a day. But that's not what the science shows. Do not exceed 60% of the maximum volume, maybe more evidence-based, but they figure teens would just ignore that so they came up with a more acceptable advice. I assumed I'd see a lot of satanic, panic nonsense from the 80s, where parents bereaved by suicide started suing heavy metal musicians. What kind of evidence did the parents present? There's been little scholarly research until this study that proceeded to try to correlate the number of statewide heavy metal magazine subscriptions to youth suicide rates. Oh, you gotta be kidding. It got really crazy, though, when researchers called psychiatric institutions pretending to be parents worried because their son started listening to that heavy metal music even though they made it clear that their son didn't exhibit any symptoms of mental illness, no drugs, no alcohol, and was doing fine at school. 10 of the 12 facilities believed the son required psychiatric hospitalization. Imagine what that would do to a kid. Turns out, if you actually come back a few decades later, metalheads were significantly happier in their youth and appeared better psychologically adjusted than their peers. Some studies were just strange, do Parkinson's patients walk better listening to Yellow Submarine or Master of Puppets? Other studies were just like, duh, heavy metal musicians exhibit a higher heart rate than those performing contemporary Christian. Much of a shocker. Some studies were kind of cute, the influence of music on promoting patient safety during surgery. Veterinary patients, kitties getting spayed with little earphones on their head. Turns out that Adagio for strings may be more relaxing than ACDC. Our review on music therapy for human patients warned that caution should be exercised when guiding patients in selecting their music as chaotic music, such as hip-hop and metal, is not healing to human cells, with three citations no less, though two of them don't say anything, and the third is a nursing newsletter merely quoting someone's opinion. But I did some digging, and it turns out stomach cancer cells like metal. If you play them cannibal corpse versus Beethoven, 12 hours of death metal increased their growth in a Petri dish. That's so metal. But who puts headphones on their stomach or their chests for that matter? Well, in one study Mozart killed off one type of breast cancer cell line and not another. In another study, only Beethoven's fifth seemed to work in Mozart flopped when the Petri dishes were surrounded by speakers and little platform. How did they even get this stuff published? Anyway, the true danger from heavy metal is headbanging. Headbanging is a contemporary dance form consisting of abrupt flexion extension movements of the head commonly seen in heavy metal. The number of avid aficionados is unknown, but some fans might be endangered by indulging excessively. Although generally considered harmless, health complications attributed to this practice include ripping your crotted artery, rupturing your lung, whiplash injury, and neck fracture, or in this case a subdermal hematoma. This guy reported headbanging at a motorhead concert, and all that brisk forward and backward acceleration might have ruptured his bridging veins and caused him to bleed into a skull. Bridging veins bridge the gap between the brain and the covering that lines inside of your skull. And if the veins tear, blood can build up under your skull and compress your brain. This bridging vein rupture has been demonstrated on headbanging cadavers. Again, a very metal study. It's been likened to a kind of chic and baby syndrome in adults. The researchers conclude that their case serves as evidence in support of motorhead's rock and roll reputation, but I think the real takeaway is that a potentially dangerous complication like that can result from a seemingly benign activity. And some of the brain bleeds can be massive. Hmm, why did he have a headache after headbanging at a party? Here's the CT scan. This is all blood, squishing his brain over. It's amazing he survived, though this poor guy didn't. See, you can tear more than just veins. There are two sets of arteries that tunnel into the skull, the carotid arteries in the front, and the vertebral arteries in the back. And you can tear both sets. A 15-year-old indulged in headbanging, ripping his carotid artery, which led to a massive stroke, and he presented half paralyzed and unable to speak, and died at a coma within a week. What about the vertebral arteries in the back? They're wedged into your skull, rendering them susceptible to shearing forces from extremes of neck motion, and that's exactly what appeared to happen. A heavy metal drummer tearing the wall of the artery. Now obviously all this is really rare, probably afflicting less than one in a thousand or so. What can metalheads do to reduce their risk? To prevent injury due to such headbanging, the range of head and neck motion should be reduced. Slower tempo music should replace metal, good luck with that. The frequency of headbanging could be only on every second beat, that's actually not a bad idea, or personal protective equipment should be used. What, like a neck brace? Little formal injury research has been conducted on the worldwide phenomenon of headbanging, so researchers constructed a theoretical headbanging model with enough physics terms to make any nerd happy, angular displacement, sinusoidal motion in a sagittal plane, amplitude of the displacement curve, study participants, headbangers, but you do need a control group, easy listening music. Head injury curves? Neck injury curves, based on headbanging tempo and angular sweep. At an average headbanging tempo, we're trying to keep the range of motion under 75 degrees, so something like this. So to minimize the risk of head and neck injury, headbangers should decrease the range of head and neck motion. Oh, there's that personal protective equipment again. Unfortunately it is difficult, if not impossible, to change the habits of heavy metal aficionados. Maybe what we need are metal studded neck braces.