Vomit Warning: How Throwing Up Can Cause a Stroke

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Vomiting is a distasteful subject most people don’t touch, which is why we never learn the correct way to vomit. As a result, people risk potentially fatal health problems when they throw up, some of which will blow their minds, literally.

Scientists have studied the physiology of vomiting, but to remind anyone who doesn’t remember what vomiting feels like, there is a tremendous pressure that arises within the abdomen that propels partially digested food from the stomach and intestines out of the mouth. This pressure you also feel in your head, as your face turns red, your eyes bug out, and your sinuses fill with mucus. Essentially, pressure in the head and all its organs increase when you throw up, including in the brain, eyes, ears, and sinuses.


Sometimes, the pressure created in your head due to the vomiting can be large enough to burst a blood vessel in your eye, called a subconjunctival hemorrhage. According to the American Optometric Association, these broken blood vessels in the eye, “May be from increasing pressure in the head from straining, lifting heavy objects or vomiting.”

Of course, if vomiting can break eye blood vessels, then it can do the same to your brain. When that happens, it’s called a hemorrhagic stroke. If it happens in the space between the brain and the skull, it’s called a subarachnoid hemorrhage. In both cases, the pressure inside the blood vessels in the brain is too great, and the wall of a vessel can burst, causing the brain to bleed. This can result in all sorts of brain problems, including death. 

Interestingly, vomiting is a symptom of strokes once they occur. Many people are brought into the hospital after a stroke with signs of having vomited. However, the current medical approach is to consider vomiting a symptom of having had a stroke, and not the cause of the stroke. Of course, it can be both the symptom and the cause, but the causal aspect has been overlooked and ignored.

Realize that there are also ischemic strokes, where the blood vessels in the brain get blocked by a clot or plaque and this leads to reduced blood supply to parts of the brain. Most strokes, about 70%, are of this ischemic type. Interestingly, vomiting is more associated with hemorrhagic strokes than ischemic strokes, which is what you would expect if the cause of the hemorrhage is pressure from vomiting. 

A 2016 study published in the British Medical Journal, entitled, Vomiting Should be a Prompt Predictor of Stroke Outcome, discovered that vomiting was seen in 14.5% of all stroke patients. When subdivided according to stroke type, vomiting was observed in 8.7% of ischemic strokes, 23.7% of bleeding strokes, and 36.8% of subarachnoid hemorrhage cases. 

The medical research into strokes and vomiting always assume that the vomiting is a result of the stroke, without asking whether the vomiting precipitated the stroke. 

It seems obvious that vomiting increases head/brain pressure, although it is hard to find a study where they measured brain pressure during vomiting. But we all feel it when we throw up.  

This is especially a problem for people with weakened blood vessels in their brains due to genetics, or to years of extra brain pressure. These weakened blood vessel areas are called aneurysms, which balloon out under pressure to the point of breaking, at which point there is a hemorrhagic stroke. Lifting heavy objects, holding in a sneeze, and vomiting are some ways we suddenly increase blood pressure in the brain enough to possibly break an aneurysm and have a stroke. 

In summary, research shows that vomiting is associated with bleeding strokes, and that vomiting can cause blood vessels to burst in the brain, eye, and subarachnoid space. It seems logical and obvious that vomiting can cause a stroke, although the medical literature only mentions vomiting as a symptom of a stroke and not the cause. 

Now that we know vomiting can cause a stroke, is there a way to more safely vomit? Put differently, is there something about the way our culture trains us to vomit that we can change to reduce the risk of stroke?

Actually, there is a way to improve the way you vomit. And it all has to do with where you vomit.

When people in modern societies vomit, they usually rush to the toilet bowl. In a modern house with indoor toilets, where else would you go to vomit? While it hasn’t been researched, it is probable that most modern people vomit in the toilet bowl. But while this seems sensible from a clean-up perspective, it does harm to your brain.

Brain circulation is affected by gravity. When you stand up, your brain is above your heart, and gravity pulls the blood from your head back to your heart. Gravity also resists the pumping of blood to the brain from your heart. However, when you bend over or lie down, your brain is lowered relative to your heart, and the gravity relationship between the two changes. With the head and heart on the same level, as when sleeping in bed or bending over the toilet to throw up, the blood pressure to the brain is not resisted by gravity as the heart pumps blood to your head. Likewise, there is no gravity pulling the blood from the head down to the heart when the head and heart are on the same level. This results in a red face, pressurized eyes, pressurized sinuses, and a pressurized brain. 

I have written about the effect of gravity and sleep position, and how head of bed elevation when sleeping can prevent, and cure, a host of problems associated with excessive brain pressure, including migraines, sleep apnea, stroke, glaucoma, and Alzheimer’s. See my article Heads Up: The Way You Are Sleeping May Be killing You. In the case of vomiting, there is increased brain pressure already being created by leaning over the toilet bowl. As you vomit, your body convulses, and your brain pressurizes, adding to the pressure of bending over the toilet bowl. 

People with weakened brain blood vessels, or cerebral aneurysms, do not always have symptoms. According to the American Stroke Association, “We usually don’t know why an aneurysm bleeds or exactly when it will bleed. We do know what increases the chance for bleeding: High blood pressure is the leading cause of subarachnoid hemorrhage. Heavy lifting or straining can cause pressure to rise in the brain and may lead to an aneurysm rupture. Strong emotions, such as being upset or angry, can raise blood pressure and can subsequently cause aneurysms to rupture.”

The first sign of an aneurysm may be when it breaks after you vomit into the toilet. And remember that eye bleeding happens with vomiting, so you don’t necessarily need an aneurysm to break a blood vessel in the head and brain when vomiting.

This begs the question, is there a better place to vomit so your head is not extra pressurized by leaning down and over a toilet bowl? 

Clearly, the less you lower your head to vomit, the less you will pressurize your head. So here are some suggestions to make vomiting less harmful to your head, and possibly help you avoid a stroke.

1. If you can, throw up in as standing a position as possible. You will instinctively want to bend over a bit, but a toilet bowl is much lower than you need to effectively vomit. 

2. Try using the sink to vomit. This adds the ability to check out what you are throwing up, in case that is important, or interesting. Or try using a “barf” bag, or other container you can hold.

3. Practice other ways of reducing brain pressure to prevent aneurysms, including sleeping with the head of the bed elevated slightly. 

4. If you experience a severe headache or other brain/nervous system problems after vomiting, consider the possibility of a stroke, and tell you healthcare provider about the vomiting. 

5. Keep in mind that COVID and other diseases which increase vomiting can also increase stroke risk. Tell you doctor about this, since they will not think of this themselves. 

In conclusion, vomiting is bad enough without it also causing a stroke, which can kill or disable you. The cultural practice of using a toilet bowl for vomiting exposes people to episodes of very high brain pressure, which can be fatal for some if it leads to a stroke. By vomiting in a more erect posture, and practicing head of bed elevation to reduce brain pressure when sleeping, you can protect your brain from the hazards of vomiting. You should be able to throw up without blowing up.




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