How Does Postural Orthostatic Tachycardia Syndrome Work?

I don’t know about you, but my POTS (postural orthostatic tachycardia syndrome) symptoms have started getting worse as we get closer to summer. It is incredibly frustrating, but I can’t control the weather, and my symptoms always get worse as it gets warmer. This means that I’m talking about POTS more, both online and in person, and that I’m also explaining this extremely weird condition a lot more than usual. One question I’m getting – beyond “What is this weird condition?” – is, “How does postural orthostatic tachycardia syndrome work?”

Of course, to answer that I do also have to answer that first question, also known as “What is POTS?”. After that, I’ll explain how POTS is diagnosed so that, if you’re reading this because you think you have it, you can figure out what your next step is if you have POTS-like symptoms. Whether you think you have POTS, you know someone who has/might have POTS, or you’re just curious, I hope that this post helps you!

As a reminder, I’m not a doctor or a medical worker. I’m a patient! I’m speaking about my experiences, and when I include medical information, I always include sources.

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What Is Postural Orthostatic Tachycardia Syndrome?

Postural orthostatic tachycardia syndrome – or POTS – is a condition when the autonomic nervous system doesn’t work correctly. The National Institute of Health (NIH) explains that the autonomic nervous system “controls involuntary actions such as digestion, breathing, production of tears, and the regulation of blood pressure and body temperature” (x). Basically, it’s the system that controls things your body does automatically. Any time that system doesn’t work correctly is called dysautonomia, or dys- autonomia. As the Cleveland Clinic says, “Dysautonomia refers to a disorder of autonomic nervous system (ANS) function that generally involves failure of the sympathetic or parasympathetic components of the ANS, but dysautonomia involving excessive or overactive ANS actions also can occur” (x).

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Basically, your autonomic nervous system can work not well enough or go way overboard, depending on the condition. The Cleveland Clinic also says, “Dysautonomia can be local, as in reflex sympathetic dystrophy, or generalized, as in pure autonomic failure. It can be acute and reversible, as in Guillain-Barre syndrome, or chronic and progressive. Several common conditions such as diabetes and alcoholism can include dysautonomia” (x). My understanding from this medical verbiage is that a lot of dysautonomic conditions can involve multiple systems; diabetes, for example, is generally considered to be an endocrine disorder over a dysautonomic one. I’m not going to pretend that I’m an expert in dysautonomia outside of my own lived experience, which is why I’m quoting from experts, so I can’t explain how those illnesses work beyond POTS.

Something I found interesting when researching this blog post is that “Dysautonomia also can occur as a primary condition or in association with degenerative neurological diseases such as Parkinson’s disease. Other diseases with generalized, primary dysautonomia include multiple system atrophy and familial dysautonomia” (x). The first part of that quote makes sense to me because if you have a degenerative neurological disease, your neurological system in general is breaking down over time, so it makes sense that that would include your autonomic system. I didn’t know what familial dysautonomia was, but the NIH says, “Familial dysautonomia is a genetic disorder that affects the development and survival of certain nerve cells. The disorder disturbs cells in the autonomic nervous system” (x). This is a great example of how dysautonomia works, which is why I’ve included it, as developing cells and continuing to keep cells alive is definitely something that your body does automatically, plus the cells referenced in this specific case are autonomic cells. Basically, there’s a lot of your body that runs or is supposed to run automatically, and you don’t always realize that it’s possible for that to not work correctly.

Okay, now that we’ve talked about dysautonomia in general, let’s talk about POTS specifically. The Cleveland Clinic explains that “Postural orthostatic tachycardia syndrome (POTS) is a condition that affects circulation” (x). This is a unique condition where, if you have a medical background, all of the words in the name explain what the condition is. Basically, postural orthostatic tachycardia syndrome is when you get orthostatic tachycardia when you go postural. But if, like me, you don’t have a medical background other than as a patient, those words mean nothing to you. So let’s discuss the entire point of this post: how postural orthostatic tachycardia works and what it is.

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How Does Postural Orthostatic Tachycardia Syndrome Work?

POTS is a form of orthostatic intolerance. The Cleveland Clinic says, “The primary symptom of an orthostatic intolerance is lightheadedness, fainting, and an uncomfortable, rapid increase in heartbeat,” and that rapid increase in heart rate is called tachycardia (x). Like I said earlier, these symptoms happen when we patients go postural, or sit up from a lying-down position or stand up from a sitting position. If you have POTS, in these situations your heart rate increases to tachycardia, aka above 100 beats per minute (x).

This happens because with POTS, blood pressure and heart rate are not working together as they should. “Heart rate and blood pressure work together to keep the blood flowing at a healthy pace, no matter what position the body is in,” the Cleveland Clinic says. “People with POTS cannot coordinate the balancing act of blood vessel squeeze and heart rate response. This means the blood pressure cannot be kept steady and stable” (x). So the symptoms of being lightheaded, fainting, and feeling nauseated, among others, are reactions to those things. When these symptoms happen frequently when going from sitting to standing, POTS is possibly to blame.

The way I explain it is that your blood pressure drops or stays the same when your heart rate is increasing. For me specifically, it’s good that my blood pressure doesn’t rise to be equal with my heart rate because my heart rate is atrociously high. For example: I’m currently writing this on the Sunday before this post goes up, and I just had to get something out of the oven. Even with POTS medication and the lifestyle changes I’ve made for this condition, my heart rate rose by 15 BPM when I stood up from sitting down. Before medication and the lifestyle changes, it would rise by way over 30, and it has taken a really long time of taking and doing those things for my resting heart rate to get below 100 BPM. If my blood pressure was the high level that corresponded with my heart rate, I would have plenty of other health issues to deal with.

But let me get back to the main question: how does POTS work? Logistically, “When you have POTS, most of your blood stays in the lower part of your body when you stand up” (x). This causes problems because – and I know this is going to be shocking 😉 – your brain and the rest of the upper half of your body need blood. So to try to fix this, “your heart beat[s] faster to try to get blood to your brain” (x). That then causes you to be nauseous, to be light-headed because your brain doesn’t have all of the blood it needs yet, and to possibly faint.

John Hopkins Medicine says that POTS symptoms come from a combination of lower-than-normal amount of blood in circulation in general, as then its easier for your brain to be low on blood; excessive pooling of blood below the level of the heart when you’re upright; and elevated levels of certain hormones like epinephrine (x). My understanding is that which things cause the reaction can depend on the person and even the situation. For example, if I’m extremely stressed, I’m more likely to have a bad POTS day than if I’m not.

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How Is Postural Orthostatic Tachycardia Syndrome Diagnosed?

The official way to diagnose POTS is through a tilt-table test. This is pretty much exactly likes it sounds like: they put you on a table and tilt you. More specifically, they measure your blood pressure and heart rate while they tilt you to see if you have the POTS reactions to being at certain levels. They start with you being flat for several minutes, then they tilt you so you’re at a diagonal for several minutes, and then they put you upright for several minutes. If I remember correctly, my test was 10 minutes at each position. If you have POTS, this is an extremely unpleasant experience.

Hopkins Medicine says that you might have POTS if you have these 3 experiences while doing the tilt-table test: your body produces an abnormal heart rate response to being upright, specifically your heart rate increases by over 30 beats per minute; your symptoms get worse when upright; and you don’t develop orthostatic hypotension in the first three minutes of testing (x). Orthostatic hypotension is “a form of low blood pressure,” and you will only be diagnosed with POTS if you don’t have orthostatic hypotension (x).

Before ordering a tilt-table test, your doctor might order a whole bunch of other cardiac tests to rule out other reasons for your symptoms. Back in 2017, when I developed POTS, I was hospitalized for several days when I had intense symptoms. Because I have RA, my doctors were concerned that my symptoms might be because I had heart damage (which is possible for RA patients despite being in my twenties). The hospital ran all the cardiac-specific tests they could think of, and they came to the conclusion that I probably had POTS, but they didn’t want to officially diagnose me because they were unfamiliar with it. As it took a while after that to get an appointment with my now-cardiologist, I started making the lifestyle changes suggested by my friends with POTS.

Once I got an appointment with her, she did the unofficial POTS test. I call it “unofficial” because, while it can give serious results, insurance companies often won’t cover POTS treatments unless the tilt-table test is completed. The unofficial test is basically your doctor measures your blood pressure and heart rate while you lay down, sit up, and then stand up. In my experience, she did this test and based on those results, as well as the results of the tests done while I was hospitalized, ordered the tilt-table test.

And that’s that! I hope this post helped explain this weird condition a bit more. And good luck to all my fellow POTS patients as we get closer to summer!

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Like this post? Check out:

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