There has been concern—and for some even fear—in the yoga community regarding the risk of strokes from doing yoga. How realistic is this?
Much of this fuss was set off by the New York Times writer William Broad, who warned that all the stretching of the neck in various yoga poses like Cobra and Shoulderstand could lead to tearing of the linguini-like vertebral arteries that run along either side of the neck bones, which could then lead to bleeding into the brain. But as I (and others) have written (see Man Bites Down Dog), Broad's analysis was alarming, lacked data to back his extraordinary contentions, and in all likelihood was way off. Still, it may be worth discussing the risk of strokes and what thoughtful yoga practitioners and teachers can do to prevent them.
Arteries of the Neck (from Gray's Anatomy)
Vertebral artery tears and resulting strokes often happen when someone makes an unaccustomed neck movement. The example that is often cited is when an elderly woman drops her head back into the hairdresser’s sink. In such a case, the movement in question is an extension of the neck (the cervical vertebrae), not so different from what happens in backbends like Cobra pose and Upward-Facing Dog. But it’s also at least theoretically possible to tear the artery when you go in the other direction and flatten the neck vertebrae, as in Shoulderstand and especially Plow pose. Even twisting poses could cause problems if you crank the head too far. Outside of yoga, such strokes also have been reported to happen when people simply turn their heads to the side or suffer minor trauma. It is estimated that 1.5 people out of every 100,000 suffer vertebral artery-related strokes every year.I have observed many yoga students who hyperextend their necks in poses like Cobra and others who flatten their neck in poses like Shoulderstand and Plow. In the case of backbends, many students have the habit of over-arching from the neck. They compress the backs of their necks, and often arch too much from the back of the skull (the occiput), at the atlas-occipital joint. (The atlas is another name for the first cervical vertebra.) This habit is common in those with tight thoracic spines. When the thoracic spine is stubborn, people sometimes overcompensate by overarching the more flexible cervical and/or the lumbar spines. In other words, when one link in the chain is tight, people tend to move more than they should from the links above and below it.
When instructing backbends, I encourage students to try to keep the back of the neck long. Rather than looking up in a pose like Cobra, I encourage those with the habit of neck hyperextension to keep their gaze forward, which tends to keep them from tipping the head back too much. It’s also useful to think of originating the movement in your neck from the middle of the thoracic spine and the lower cervical vertebrae (where the neck attaches to the back).
Poses like Shoulderstand and Plow pose tend to flatten the neck. This is especially problematic if the student tries to move the chin towards the chest (an unfortunate instruction that some yoga teachers use). Instead, I encourage students in these poses to lift the front of the chest toward the chin, and actually slightly move the chin away from the chest. If you try this, you may notice that it lessens the feeling of pressure at the back of the neck.
In the traditional hatha yoga Shoulderstand, known as Viparita Karani (not to be confused with the restorative pose that uses the same name), the legs are in a jack-knife position. In other words, the pelvis is behind the spine and the feet are forward of the spine. This pose can be done safely without any props, especially if you follow the instructions of moving the chin slightly away from the chest. This is the version of Shoulderstand I’ll do if I wind up somewhere with no props.
Rare is the yoga practitioner who is flexible enough to do the modern, more-directly vertical version of the Shoulderstand—in which the legs are stacked directly over the hips and shoulders—without blankets or other props to raise the shoulders off the ground. To keep suppleness in your neck, the number of blankets required varies. For example, I use four folded blankets under my shoulders. Try to place your shoulders near the edge of the folded blankets so you graze the skin over C7, the lowest cervical vertebra, while you work to lift C7 away from the ground. Your breath should be soft, slow and even throughout the pose, and if at any point you can’t breath smoothly, or otherwise feel uncomfortable come down.
Plow pose is even more challenging to the neck, and I recommend the same blanket set-up. If you notice any discomfort at the back of the neck, however, I recommend either skipping the pose entirely or placing your feet higher, for example, on the seat of a chair.
In twists, try not to lead with your head. In other words, the turn should come from the vertebrae all along your spine, with no twist whatsoever from the atlas-occipital joint. One instruction I give if students feel any tension in the neck is to turn the head ever so slightly (say 1 millimeter) in the opposite direction of the twist. What this accomplishes is to stop people from trying to twist the skull on C1, a motion those joints are not meant to do. Even more conservative, is to not let the chin turn any more than the chest, in other words the nose and chest point in the same direction.
Beyond lessening the theoretical risk of a vertebral artery stroke, all the above advice will also tend to help avert yoga’s contributing to such musculoskeletal problems of the neck as arthritis and overstretching of spinal ligaments. Indeed, averting these problems is actually my primary reason for recommending doing the poses as I suggest. Broad generated tremendous publicity for his book by trumpeting the risk of vertebral artery strokes, and made the absurd, entirely unscientific calculation that yoga causes 300 strokes and 15 deaths per year in the U.S. My guess is that it’s more like in a one in a zillion scenario.
Ironically, skillfully practicing the very poses that Broad recommends avoiding might actually lower the risk of the vertebral artery strokes. When you gradually stretch the arteries and surrounding tissues as could be expected with a regular yoga practice, the vessels would likely become more pliable, and resistant to tearing with sudden movement or trauma.
And the bigger picture is that vertebral artery strokes are a tiny percentage of all strokes, estimated to strike 269 people per 100,000 every year. Yoga’s documented ability to lower blood pressure, cholesterol and stress hormones, reduce inflammation, thin the blood, etc., in all likelihood greatly lowers the incidence of all types of strokes—as well as heart attacks and a host of other conditions. Just be sure to be mindful of contraindications. So, for example, if you have poorly controlled high blood pressure, you probably want to avoid inversions like Headstand entirely. The risk of having a stroke as a result is probably small, but it’s better to err on the side of caution.
