I’ve found when I meet people who are unfamiliar with POTS they can get hung up on what causes the symptoms I’m talking about. I think of it as cascading symptoms in that one primary symptom then causes several further symptoms, which can then cause further symptoms, etc...
I thought I’d write out the basic symptom cascade I experience with my POTS. Disclaimer: this is not a conclusive list of POTS symptoms and it is not the same experience everyone has. I am also not going to get into treatment options as it would potentially get confusing to talk about in the same post. It’s much easier to understand treatment options after you understand the basic symptoms you are trying to treat.
One of the most common POTS symptoms is inappropriate vasodilation. In layman’s terms what happens is when I become upright (standing or sometimes even sitting up straight) gravity acts on the blood inside my body. The blood is pulled downwards into my abdomen and legs. This happens to everyone but in a healthy person their bodies can react by constricting the veins and arteries which counteracts this problem in a matter of seconds. My body on the other hand is unable to respond appropriately, so the blood continues to pool in my lower extremities. Since I have a finite amount of blood this means that there is extra blood in the lower parts of my body and not enough blood in the upper parts of my body (where most of my vital organs are).
My body does have a backup mechanism for solving this problem. If I don’t correct it in some other way I will eventually pass out. Once that happens my body will generally become horizontal again (as I’ll probably be laying on the ground) and proper blood flow will be restored. This is the most extreme scenario but there are also lots of other things that happen in my body when my blood flow to my brain, heart, lungs, etc… is lower than it should be.
Let’s start with the heart. When this happens my heart registers that it isn’t getting enough blood and assumes that there is just simply not enough blood in my body. To compensate for this it starts beating faster. If there’s not enough blood then the heart thinks we just have to work harder to make everything work. So my heart rate increases significantly. When standing up a healthy person’s heart rate will increase about 5-10 beats per minute. In POTS patients you are looking at 30+ beats per minute. With other factors it can easily be more. For instance, heat makes this whole process more extreme, as does lifting your arms above your head. Once in the shower while washing my hair my heart rate hit 192 beats per minute.
When my heart rate increases that much in a short time it signals to my body that something is wrong. This sets off my fight or flight response. That response is handled by something called the Sympathetic Nervous System. There is also a Parasympathetic Nervous System which does the opposite (rest and digest). So my sympathetic nervous system kicks into high gear which leads to chemicals being released in my body that would help me to either fight or run away from danger. Except there is no actual danger so my body doesn’t have any real use for this response. If you’ve ever been in an accident or a very scary situation you might have noticed you feel shaky and kind of weak afterwards, that’s because when the fight or flight wears off you’re body is very tired and needs to rest up. Now imagine that happening every time you stand up.
Those chemicals that are released in the fight or flight response do a number of things. Again, these things are very helpful in a dire situation but less helpful when I’ve only tried to stand up or even if I’ve been sitting upright for awhile. They tell my body to stop digesting food. Now this is an interesting set of symptoms and not ones that was talked about in detail in most of the early literature I found when I was first diagnosed. It turns out there aren’t very many gastroenterologists who specialize in POTS.
As far as I can tell the fight or flight response tells my body to stop digesting (since that isn’t vital to my immediate survival). If you remember from earlier though I said that blood was pooling not only in my legs but also in my abdomen. One of the things that happens when you are digesting food is vasodilation. Your body tries to get more blood to the area so it can pick up all those nutrients. So I’ve got some very confused guts at this point. There is blood pooling saying, “Hey! Digest some stuff!” and a sympathetic nervous system reaction saying, “Hey! Stop digesting stuff, it’s not important right now.”
Early on after being diagnosed I was doing my homework and learning all about POTS as best I could and everything about GI symptoms just stated that they were common but didn’t explain at all what was happening. I’m sure this is in part because everyone experiences different GI symptoms but with those conflicting messages being sent it’s no wonder our guts don’t always work well or feel good.
Another thing about that fight or flight response is that the chemicals released end up causing many of the most common symptoms of anxiety. Increased heart rate, feeling nauseated, and shakiness are all tell tale signs. There’s some debate about whether people with POTS actually have anxiety. If we define anxiety by a set of symptoms then yes we do have that. If we define it by its root cause as a mental disorder than no we do not necessarily have that. Of course people with POTS can have coexisting anxiety disorders but because our symptoms look so much like classic anxiety the root cause of those symptoms is often misdiagnosed. This delays proper treatment, often for years. I absolutely benefitted from psychiatric care, but one big benefit was the confidence to say to my doctors, “No, this isn’t because of anxiety, there is something else going on.” In my experience when I’m experiencing anxiety it is significantly reduced if I can lay down for an hour or so. This would indicate that at least some part of my experience with anxiety is purely physiological in origin.
The fight or flight (sympathetic nervous system) response results in feeling exhausted as it wears off, especially with the frequency POTS patients experience it. When your body is getting revved up to high gear every time you stand up it quickly runs out of gas. Fatigue and exhaustion are some of the most bothersome symptoms of POTS. Other symptoms that are related to this symptom cascade include headaches and brain fog, both of which are presumably from the less than ideal amount of oxygen getting to my brain anytime I am upright.
The fact that POTS symptoms present in nearly all of your major bodily systems is one of the things that make it hard to recognize and diagnose. Many POTS patients are told it’s psychiatric in nature or that they are hypochondriacs by their doctors. This delays treatment and can lead to medical PTSD where patients are afraid to seek care or under report symptoms so they seem less “crazy.” More doctors are learning about POTS but it’s still very much an uphill battle still to get diagnosed and properly treated. Many patients wait years and see dozens of doctors before being properly diagnosed.
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