Does yoga cause strokes? New York Times science reporter William J. Broad has certainly been making the case that it does. In his new book “The Science of Yoga,” Broad makes the case that yoga is associated with rare type of strokes caused by either cartoid or vertebral artery dissection — tears in one of the three major neck artery that supplies blood to the brain. Serious stuff!
And yes, there is at least one documented case in the medical literature of vertebral artery dissection being linked to yoga — from 1977. Broad discusses this case at length in his book and article. It involves a 25-year-old who liked to be in shoulder stand for five minutes daily, with his neck “maximally flexed against the bare floor.”
(Broad also highlights a 1972 “article” from Dr. W. Ritchie Russell in the British Medical Journal about the supposed dangers of shoulder stand and cobra pose to the “vertebral and anterior spinal artery circulation.” But calling this an “article” is a bit of a stretch — it’s a two-paragraph letter to the editor that really is nothing more than speculation).
Of course, a) most people don’t spend lots of time in shoulder stand on a bare floor so hard as to leave bruises; and b) you can find a lot of weird cases in the medical literature. One woman, for example, suffered carotid-artery dissection — a tear in the other major neck artery — in 1997 after a 32-minute phone call. She held the phone to her right shoulder by flexing her head so she could keep ironing.
Blunt vertebral arterial injuries remain poorly characterized. The literature is replete with case reports of BVI: participation in athletics (aerobics, boxing, football, jockeying, jogging, judo, paddleball, skiing, swimming, volleyball, and wrestling), being bitten by a dog, undergoing chiropractic cervical manipulation, coughing, “bottoms-up” drinking, getting dressed in a tight diving, “head banging” to music, moving furniture, parking a car, roller coaster riding, scolding a child, seizing, vomiting, performing yard work, and practicing yoga [here the authors cite Russell] have all been associated with BVI. Unfortunately, such bizarre case reports, although interesting, do not provide a scientific foundation on which to establish management policies.
The paper’s authors, surgeons affiliated with Denver Health Medical Center, went on to report that of 38 patients diagnosed with vertebral artery dissection in a 3 1/2 year period, more than half had been involved in motor-vehicle accidents. Others had been fallen from a horse, been struck by a tornado, been assaulted and fallen 30 feet. Serious stuff, in other words.
Similarly, on VertebralArteryDissection.com, there are nine pages with about 70 different personal accounts submitted via email to the site’s webmaster from people — often young and healthy — who have suffered vertebral artery dissection. Yoga isn’t mentioned at all except by two people who said they didn’t practice. “The most worrisome part is ‘why,’” reads one report from a 39-year-old woman. It’s hard to avoid something when the reasons are unknown. I’ve had no trauma, chiropractor work, yoga, etc. … It is hard to get an answer on returning to activities because no one has a good explanation into what caused it.”
There were several people who said they suffered VAD after going to a chiropractor, others who were involved in motor vehicle accidents, one who came down with it coughing and another during a 5K race. But for others like the 39-year-old above, it’s a mystery.
Broad must have known that in order to link yoga and strokes he’d need to rely on more than just a 40-year-old letter-to-the-editor and a medical case study from 1977. So he requested all the records from the Consumer Product Safety Commission’s National Electronic Injury Surveillance System, which receives reports from 90 hospital emergency rooms across the country. Broad writes:
The 2002 survey, like that of any year, gave a brief description of each person and each injury. … The survey listed no strokes — their diagnosis would typically require detailed examinations that went beyong the simple capabilities of most emergency rooms — but several cases listed symptoms that might have coincided with the precipitating damage. “Acute neck pain,” read one write-up. “Collapsed to the floor while performing yoga,” read another.
But — I have the same NEISS records Broad does, and the evidence doesn’t support the scary picture he’s painting. There were two cases of yoga-related “acute neck pain” reported to NEISS hospitals in 2002 — but both were diagnosed as strains, and both patients were treated and released. The 40-year-old woman who “collapsed to the floor while performing yoga” and went to the ER four days later, Feb. 1, 2002, also was treated and released after being diagnosed with a possible seizure.
Obviously, if physicians suspected a patient had suffered a stroke, they wouldn’t be treated and released. From 2002 to 2010, there were only a handful of cases of yoga-related head or neck injuries where the patient was admitted or transferred:
- One 58-year-old woman suffered an intracranial hemorrhage (bleeding within the skull) while practicing yoga March 8, 2006.
- An 86-year-old woman fell and hit her head on a pool table while practicing yoga Dec. 27, 2004.
She was diagnosed as having fainted, and suffered lacerations and a fracture.
- A 39-year-old woman performing yoga in a highly heated room May 23, 2009, started to experience a headache with loss of vision, tingling and numbness. (The diagnosis code says H/A, which I assume stands for headache, but she was admitted.)
- A 57-year-old woman was accidentally struck on the head during a handstand in yoga class July 22, 2009, and had a worsening headache since.
That’s it — out of monitoring 90 hospitals for eight years, those are the ONLY yoga-related head or neck injuries where a patient was admitted. Even if we assume for the sake of argument that the 57-year-old and the 58-year-old had suffered a stroke — a BIG assumption — that would translate into a national estimate of 30 cases every eight years, or about four a year. And neither of those cases describe the type of neck pain associated with cartoid or vertebral artery dissection (although, to be sure, the intracranial bleeding is certainly very serious).
In his book, Broad later goes on to criticize a 2001 article in Yoga Journal that discussed the possible risk of arterial dissection as it relates to yoga.
The magazine then proceeded to downplay the threat to by failing to put the issue in perspective. It said doctors had found injuries to the vertebral arteries from all causes (such as yoga, beauty salons and chiropractors) to be rare — annaully, a person and a half out of every hundred thousand.
This was accurate. But it ignored the big picture. If twenty million people in the United States did yoga — a standard figure — and if yogis suffered the injury at the same rate as the general population (a very cautious assumption, given all the neck twisting and bending), that meant three hundred yogis in the United States faced the threat of stroke each year, or three thousand over a decade. … Then, in what was apparently meant to be more good news, it added “Death results in less than 5 percent of the cases.”
Here again, the figure is correct but misleading because it failed to put the number in perspective. If three hundred yogis in the United States suffered injuries of the vertebral arteries each year (the lowball estimate), 5 percent of that would be fifteen — fifteen yogis who lay dead after wounds to their vetebral arteries resulted in brain injuries serious enough to kill. And the real number of fatalities, despite the percentage being ‘less than’ five, was probably higher given the large number of poses in yoga that involve extreme contortions of the neck. Maybe it was thirty fatalities annually, and maybe three hundred over a decade. Globally, the fatalities might number in the thousands. It was an open question.
The flaw in Broad’s logic is so obvious here, it’s astonishing the man is a science writer. Putting the figure in perspective involves not calculating the number of yogis who suffer arterial dissections — but the number of yogis who suffer arterial dissections related to yoga. I mean, it’s tragic if a yoga practitioner falls off a horse and tears a neck artery — but that has nothing to do with yoga.
Broad could just as easily compile a scary list of the hundreds or thousands of yogis who die each year in automobile accidents. What’s relevant isn’t the total number of injuries or deaths to practitioners — it’s the additional risk, if any, posed by the practice. And so far, Broad hasn’t presented any evidence that yoga practitioners do suffer strokes at a greater risk than the general population.
Last week, Broad gave an interview to the blog Well + Good NYC in which he was asked about the controversy:
Okay, but one of the most common criticisms of the excerpt is that you didn’t compare the rates of injury to other physical activities and that the number of injuries was so small that it was overblown.
I know. People say, these injuries are similar to sports injuries or injuries you get from any physical activity, and I go, ‘Really? Strokes? Parts of your brain dying? People dying from strokes?’ This type of stroke kills about one in twenty people — they’re one of the most serious injuries you can suffer, and they’re not associated with running, or even football, which does have a record of brain injuries.
This is wrong on two levels. First, there are more documented cases in the medical literature of people suffering artery dissections after running or playing football than of practicing yoga. (Playing tennis and golf, riding roller coasters, sneezing and severe coughing been also linked to vertebral artery dissection).
Second — it’s just ridiculous for Broad to assess the risk of yoga based on one very rare injury. Yoga isn’t associated with heart attack, while running is, for example. To put risks in their proper perspective, you have to look at the full spectrum of serious injuries, and even exercise-related deaths … here’s a grim list of all the exercise-related fatalities reported to NEISS hospitals from 1997-2010. (Mostly heart attacks from jogging or working out).
Basically — the bottom line is — yes, you can probably suffer a stroke from twisting or putting pressure on your neck in certain yoga poses. But you can suffer a dissected artery sneezing, painting a ceiling or riding a roller-coaster. Overall, all of these activities are very safe. Ignore scaremongers like Broad and go out there and live your life!