Episode Transcript
E190: Causes of Common POTS Symptoms with Dr. Cathy Pederson
[00:00:00] Jill Brook: Hello fellow POTS patients and most appreciated people who care about POTS patients. I'm Jill Brook, your hyperadrenergic host, and today we are going to discuss exact causes, i. e. mechanisms of action, of common POTS symptoms. So, if you have ever wondered what the heck is going on in your body when you feel brain fog or lightheaded or dizzy or whatnot, this is a chance to hear answers from our favorite neurobiology professor and president, founder, and MVP, Dr. Cathy Pederson. Dr. Pederson, thank you so much for being here today.
[00:00:34] Dr. Cathy Pederson: Thank you, Jill. I'm glad to be here.
[00:00:37] Jill Brook: So how do we introduce this topic? Is there anything we should talk about before we dive into particular symptoms? Do we really know what's going on? Is this kind of guesses? Is there good research on this?
[00:00:49] Dr. Cathy Pederson: I think it's a mix. There are some where there are some good research. There's some where it's really just sort of General knowledge and thinking that this is what's going on. But either way, hopefully it will help folks to think about some of these common symptoms and what maybe they could still be investigating to try to improve those symptoms.
[00:01:13] Jill Brook: Yeah, I guess it always comes back to there's probably some harmless things you can try, and if you can, why not?
[00:01:20] Dr. Cathy Pederson: Right.
[00:01:22] Jill Brook: Okay, so let's start with the one that people seem to ask about the most. Brain fog. What the heck is going on with brain fog?
[00:01:31] Dr. Cathy Pederson: Yeah, this is an interesting one. I think it's super common for people with POTS. And I remember, it's probably been 10 years ago or so now, we went in and we listed this as one of my daughter's worst symptoms. She was a student, still is a student, and the doctor said, I don't even know what brain fog is.
Like, clinically, it's really amorphous, but I think that it really is anything that's affecting your ability to think. And, you know, so for my daughter, we see confusion, you can see it in her eyes, right, where she just is not thinking the way that she should be, could be disorganized thinking where you're sort of jumping from one thing to another, trouble concentrating or focusing on what you're trying to do, and then trouble putting words together. Having difficulty articulating your thoughts can also be a symptom of brain fog.
[00:02:28] Jill Brook: That's the one that I get. I feel like my vocabulary sometimes goes down to like a first grade level.
[00:02:34] Dr. Cathy Pederson: yeah, I think that's not uncommon. And it's frustrating because in your head, you sort of know what you want to say, but you cannot bring up the words to articulate that.
[00:02:45] Jill Brook: Okay, so do we have any idea what the potential causes might be?
[00:02:52] Dr. Cathy Pederson: Well, I think there are a lot of potential things that could contribute. Notice the dancing around that I'm doing here. So there are some things that maybe you could talk to the doctor about, ask them if they've tested for some of these things. So one is inflammation. And I think in the last decade or so, there's been a fair amount of talk about systemic inflammation.
Meaning that your whole system is sort of activated and seems like it's fighting something. It's not like it's an infection in your lungs or an infection in your skin, let's say. And so there are some tests that doctors will often run. You can look through your own blood tests. One is C reactive protein.
So that's one that they use to look for this inflammation in the body. Another one is the sedimentation rate. Usually looking at erythrocytes, the red blood cells, and then the last one I think is a lot less common, that's called plasma viscosity, looking at the thickness of the watery part of your blood. But all of those can give the practitioner an idea about whether you have this widespread inflammation or not. Another possible one is anemia, and so anemia is not uncommon in women. Particularly women who are having their period every month. And so one of the big causes of anemia is not having enough red blood cells in your blood. And the red blood cells, of course, are the ones that are carrying oxygen to all of your tissues, including your brain. And so this could be affecting brain fog as well. So that's an easy blood test.
Another blood test they can run is to check the thyroid. so particularly if people have what's called hypothyroidism, meaning that their thyroid is underactive. It's not as active as it should be. That thyroid is supposed to be regulating your metabolic rate and it does that for all the tissues, including the brain. And so that's another one to look at. There can be hormone changes, and so sort of famously in pregnancy, women have sort of a brain fog, right? They call it pregnancy brain. But in that case, their estrogen and progesterone levels are really, really high as a result of that pregnancy.
But we also see this in menopause that women feel like they're losing their minds sometimes as they're going into menopause that they can't balance all of the things mentally that they used to be able to. And in that case, the estrogen and progesterone had dropped really low. So there are some hormone changes in either direction that could contribute to the brain fog.
And then I was doing an interview recently on the Amateur Activist podcast and Isabel Herrera, who's the host of that podcast, was talking about she started to take vitamin B12 and that for her, and I'm sure she had a deficiency, but that for her, she felt like her brain was turned on again.
I'm like, oh my gosh. Is this how other people are functioning? And so it flipped a switch. So that's not going to help if you're not deficient in that. But that can really help some folks. There can be allergies or sensitivities that do things like this as well. So an allergy to aspartame, peanuts or dairy can increase brain fog.
And I want to say here, it turns out that both of my girls have a milk allergy, but I didn't know it. And we found this out through blood tests, and they were still young at the time, they were kids, and you know, with kids, you're always wanting them to drink a lot of milk. Boy, when we changed from cow milk, To almond milk, big change, but it was not something that every time they drank milk, they felt worse.
So I just want to point that out to folks, that it could be something that's in your diet that you're not even realizing until you get rid of it, that it could be contributing.
[00:07:16] Jill Brook: Yeah, that's so interesting, and when you mention allergies and inflammation, of course there can be different reasons for inflammation, but one that is involved with both of those things comes back to mast cells, and it reminds me of an article that came out in 2021 by Dr. Theo Theohardis. So, this is a great mast cell expert. The name of his article was long COVID syndrome associated brain fog and chemo fog, luteolin to the rescue.
So that's one of those supplements. Lutulin is a I'm having the word finding difficulty that we just talked about
Flavonoid, Flavonoid, it's one of the Flavonoids that's known to be a mast cell stabilizer and they report that they don't exactly know the mechanism of action in the brain fog. But that they suspect that it might be brain inflammation stemming from mast cells and that lutelin has been shown to help with that.
And so all these things are so intertwined. And I, I know there's more reasons for inflammation than just mast cells. And so this all gets so complex, but I like what you're bringing up which is that in inflammation. There's a lot of things in lifestyle that you could try that are probably healthy anyways.
And so another one of those nice no harm, no foul. If you clean up your diet or experiment with some things for a little while or try some lutelin Nothing too terrible can probably happen and you might help your brain fog or you might not.
[00:08:51] Dr. Cathy Pederson: Absolutely, yeah, and those of us in the community know that trial and error is just what we have to do, and it's, it's frustrating, but it is nice to have new ideas of things that you could try that are not really invasive, and that may benefit you in more ways than just brain fog as well, yeah, absolutely.
[00:09:13] Jill Brook: And if I could just say one last thing, I don't know if anybody else feels this way. This doesn't happen to me too much anymore, but I used to have a certain kind of stomach ache that would always come with a headache and brain fog, and they were somehow connected, and it was just a different kind of stomach ache than other stomach aches, and it reminded me of the whole gut brain connection thing, and I don't know what was going on, but I always thought that was kind of interesting.
[00:09:37] Dr. Cathy Pederson: Yeah. Yeah, it really is. It's so complex. And the way our medical system is set up right now, you know, people specialize in one area and what we really need are generalists almost, right? That are putting all of these things together and really trying to think holistically about what's going on physiologically and biochemically in our body.
And that's a tall order. That's tough work.
[00:10:04] Jill Brook: It is, and it reminds me of the blind man and the elephant metaphor, which I learned has been around for 2, 000 years, and we still don't have a person in medicine whose job it is to coordinate all the blind men.
[00:10:17] Dr. Cathy Pederson: Right. Absolutely.
[00:10:19] Jill Brook: Let's move on to another symptom. What about dizziness or lightheadedness? Do we know what's going on there?
[00:10:28] Dr. Cathy Pederson: Yeah, so when we're thinking about dizziness and lightheadedness, again, I think this is very, very common for people who have POTS and probably the main cause of that in POTS patients is poor circulation of the blood. And it's part of that orthostatic intolerance that we know is a cardinal symptom of POTS and so again what that means is that essentially you're allergic to gravity. That people when they are laying down or sitting feel better but when they stand up, it changes the dynamics of blood flow and so gravity when you're standing straight up pulls a lot of that blood down towards your legs and your feet, your abdomen, which means that you don't have as much blood then up at the heart and up at the brain.
And so again, if we don't have enough blood flow at the brain, that can cause that sensation of dizziness or lightheadedness that could be an indicator that we may faint. So you want to sit back down again, right? So poor circulation is certainly one. Another one that could be happening is the side effects of some medications.
So you might look at all of your medications and they will put dizziness warnings on those. If you're really having a lot of trouble with dizziness and lightheadedness and you're on a medication with that warning, talk to your doctor. Even if there's not that warning, I would talk to your doctor and be sure that they're looking because maybe a combination of things that you're taking could contribute to that dizziness or lightheadedness feeling. The third one that's probably unrelated In POTS patients, but could certainly be contributing, is inner ear problems. And so, you know, we've got this vestibular system that helps us with balance and coordination. And so, if something is throwing that off, That could also contribute to that dizziness or lightheadedness.
So again, it's worth asking the doctor about. There are some things that they can maybe do to try to help that. But I think in most cases, it really is that low blood volume, and when you stand up, that blood volume sags. It goes down towards the abdomen and the feet.
[00:12:51] Jill Brook: And if I could add a little bit of a nuance to that, I think a few times a month in the past, I have talked to patients who are working hard to drink a lot of fluids, but maybe are skipping the salt because they heard that salt was unhealthy. And so I've also seen people get dizzy from what I fear was being on their way to hyponatremia and having too much water with not enough salt, which can also do it.
[00:13:18] Dr. Cathy Pederson: Right. So in POTS, we need to get the blood volume up, but also the kidney, there are hormonal things, I don't know, we don't need to go into all the details of it, but you tend to lose more fluids when you have POTS than people who don't. So you're literally peeing it out. And so the reason that you need electrolytes in the drink, whether it's something that you're mixing in or you're buying something that has it in it, is because where salt goes water always follows.
And electrolytes are salts for folks that don't know that, right? So we need those electrolytes or those salts in the blood itself and that helps the kidney to move more water than back into the bloodstream and keep that blood volume up. So you're right, it's very, very important to not just drink water, but to have electrolyte drinks that have sodium and potassium and maybe some other salts in there as well.
[00:14:14] Jill Brook: So what can people do if they're feeling dizzy?
[00:14:18] Dr. Cathy Pederson: Yeah, I think this is a big one because it is such a part of life, everyday life for a lot of people with POTS. If you stand up and you feel dizzy or lightheaded, you know, sit back down again, then. If you happen to be standing, go to a wall and sort of slide down that wall if that's what you need to do.
What we don't want is for you to fall, you know, whether it's a full faint or whatever is going on, because then the concern is that you'll hit your head. Or you'll cause some other damage to your body, more from the fall from the fainting. The fainting's not particularly worrisome clinically. There's no real harm, but it's the fall that we worry about.
So getting back down, whether it's sitting on the floor, sitting back down on the chair, whatever you need to do is important. I think as you get up, you know, think about getting up from bed in the morning, maybe just sitting up in that bed. For 30 seconds a minute, and then putting your feet over the side of the bed for another 30 seconds or a minute, and then getting up and starting to move slowly.
So what that's doing is allowing your body to get used to gravity again in a slower way. So it's allowing that heart rate to catch up, to start pushing that blood through the body and adjusting to gravity instead of just jumping out of bed like maybe you used to do before POTS. The other thing I would say is that you want to avoid really bending over.
For people with POTS, dropping that head below the heart is not a particularly good thing to do. And so if you need to pick something up off the ground. You're better off to get one of those pincher things, right, that you can use to pick that up or to bend from the knees and try to bring the whole body down. You really don't want to just bend over and have that head moving that much closer to the ground, sort of upside down.
As you were pointing out a minute ago, I think sometimes dizziness can be related to dehydration. For And so, drinking the fluids, but again, you do need the electrolytes. It's okay to have some water.
I don't want folks to think that they can't drink water. We don't want you only drinking water. We really need some electrolyte drinks in there. And then the last thing is, if this dizziness and lightheadedness is problematic for you, you want to avoid things like coffee and alcohol. They use different mechanisms, but both of those increase water loss, and so you're peeing out more fluids, and so again, that means you don't have as much in the blood and the plasma.
The other thing is you may want to avoid cigarettes and recreational drugs that again, may increase dehydration. So dehydration is our enemy as POTS patients for sure.
[00:17:16] Jill Brook: And so, there's dizziness, there's lightheadedness, and then there's kind of the next level of severity, which is the actual fainting. Do you want to talk about that?
[00:17:26] Dr. Cathy Pederson: Right, yeah, so about 30 to 60 percent of POTS patients faint and may faint regularly. I think you used to be in that group, Jill, right? But it's gotten better, is that true?
[00:17:41] Jill Brook: Yep, for sure. Yep.
[00:17:43] Dr. Cathy Pederson: Yeah, and so I think a number of our board members actually, I think three of our board members have said the same thing. That fainting used to be big problem, but as they've learned how to sort of manage symptoms, manage diet, manage hydration, that sort of thing, maybe gotten onto medications that helped, that it's not as big an issue.
So this is something that we can be working on for sure to try to decrease, but again, it's so much trial and error. Okay, so what's going on with fainting? Boy, good question. And again, fainting is not a cardinal sign. You know, if 30 to 60 percent of people are fainting, and some people used to faint and they're not fainting anymore,
[00:18:25] Jill Brook: Well, and you hear,
[00:18:26] Dr. Cathy Pederson: to think about,
[00:18:27] Jill Brook: yeah, and you hear a lot of the POTS doctors saying that fainting is not uncommon in the non POTS population either.
[00:18:34] Dr. Cathy Pederson: right. Oh, this used to be a big problem for me, and I don't have POTS. I had hypoglycemia, I think, and I would regularly slide down the wall. I do better with eating better, exercising better, that sort of thing. But when I was in my late teens and twenties, that was a big issue for me, unrelated to POTS, which I don't happen to have.
So one thing that can cause it is something that's called reflex syncope. So syncope, of course, is the medical term for fainting. And this is a evolutionary reflex response that we have to certain triggers that will slow down your heart rate. And also, dilate your blood vessels. So when you dilate blood vessels, that means that they're getting larger in diameter.
They're getting bigger. And both of these things, slowing down the heart rate and blood vessel dilation, actually decreases blood flow to your body but also to your brain. So we're very brain focused today on this episode. And so if we're not getting enough blood to the brain that's problematic. So what could the triggers be?
I was just talking to a student yesterday who started with EDS, had huge issues with EDS. And then about six months ago, really has developed a pretty severe case of POTS. And It was interesting because she was just saying that when it's just the POTS, she does pretty well. But if she has an additional stressor like heat Or pain from her EDS.
She's had significant pain with that EDS. If one of those things flares, she faints. And so she's sort of learned to watch for those as triggers, knowing that that increases her risk. And her fainting is sort of like you've described before, Jill, where it's not you faint and within a couple of seconds you're back and everything's fine.
She'll be out sometimes for hours, and I think you've talked about that as well, right?
[00:20:43] Jill Brook: Yeah, yeah it's weird that there's a whole kind of family of different kinds of fainting, but yeah, I definitely feel like there's different flavors.
[00:20:52] Dr. Cathy Pederson: Yeah, I think so too. And so for her, and actually, these are common for reflux syncope to have those triggers being heat and pain. Anxiety or distress about something can also be a trigger. And then hyperventilation. If something else is going on, you start hyperventilating, that can also trigger that.
And so again, all of those things can cause that blood pressure to drop, and when the blood pressure drops again, less blood flow to the brain. And so that can cause that dizziness and then again that fainting. When we were talking about this episode, I had a friend actually, Caroline, who said, Oh, I just read this great article about a new finding with fainting and she sent it along.
So thank you, Caroline. That's implicating the vagus nerve. And I know that we've talked about the vagus nerve several times on the POTScast. We've had interviews that are primarily on the vagus nerve. Again, this does a lot of parasympathetic control. This is a cranial nerve that goes from the brain stem down to the heart, the lungs and the abdomen, the GI tract,
and it also has a sensory component where it's taking signals from your organs and taking it back up to the brain stem, okay? And so this new study, what it found was that some of these sensory neurons of the vagus nerve, express a chemical, a neurotransmitter called neuropeptide Y, receptor Y2.
Yeah, us scientists, we name these things very, very strangely, it's really terrible, and then they abbreviate, which I'm not going to do. But this neuropeptide Y receptor Y2 has been implicated in fainting. And so the study that was recently published was looking at this in mice. And so a lot of these studies happen in animals because we can do manipulations that we just can't do in humans. And so they triggered these These neurons, this neuropeptide Y receptor Y2, and when they triggered that in the vagus nerve, right away the mice fainted. Boom! Out they went. And what was really interesting is that the way that they fainted mimicked what you see in humans clinically. So the pupil of their eye dilated. They did a sort of an eye roll as they started to faint, and then physiologically, the heart rate dropped, the blood pressure dropped, and their respiratory rate dropped. Things that again, we think clinically we see in humans. With all of that, reduced blood flow to the brain, which is our theme of the day.
But what's interesting is, because they're doing this in the lab and they're triggering it, they had EEG machines monitoring the brain activity of these mice, and they showed that the brain activity dropped. So all of this is very interesting, right? But what's even more interesting, I thought, and again, we couldn't do this in humans, but then they lesioned essentially these parts of the vagus nerve.
They removed them from the mice. And the mice that were fainting stopped fainting. And so when you put this together, it seems to say that this neuropeptide Y receptor Y2 is implicated in fainting. Now what's interesting about this is, well, number one, we don't have anything that's ready clinically for this.
But when we get a basic science finding like this, then they can start looking for medications that block that receptor. We call that an antagonist to that receptor. And so my guess is the next step or some other lab will really start looking at how can we block this receptor and will that stop fainting in humans with POTS, but other people also that may be fainting as well.
[00:25:12] Jill Brook: So this is all fascinating, but I'm wondering, and I imagine some listeners are wondering, you mentioned that this fainting response was an evolutionary reflex, and it's preserved in different species. Is this somehow helpful to animals? What is this doing to help anybody evolutionarily, do we know?
[00:25:32] Dr. Cathy Pederson: Well, I don't think it helps humans, but I, I think evolutionarily it can help. So, you know, there are some predators that only want a live animal. And so the fainting response can actually mimic death. A lot of predators don't want to scavenge, they want a live kill. And so evolutionarily, it can allow a zebra to survive an attack from a lion or something like that, right?
In humans, that doesn't really help us very much, but there are some evolutionary reasons why this might be a good thing.
[00:26:11] Jill Brook: Well, you know what? That makes me feel better. If some zebras along the way were better off for it, I can live with fainting a little more easily. Okay. So
[00:26:21] Dr. Cathy Pederson: It is interesting to think about why these things would evolve in the first place .
[00:26:25] Jill Brook: yeah, for sure. Okay. So what should people do if they faint? What are their options?
[00:26:32] Dr. Cathy Pederson: so I think there are a few things that, that they can do. For one, let's talk to the family members first, right? So if Mike were to find you on the ground and you have fainted, what should he do to sort of help that? The first thing is if they're not laying on their back already, put them on their back.
That's the safest position for them to be in. And what we want to do, here's our theme of the day, is get blood flow back to the brain. So, you want to elevate the legs. If you can put a pillow or a coat or something under their legs, we want to raise the legs about 12 inches, and again, the idea is that if that blood volume has moved to the abdomen and the legs, we want it to move back towards the heart and the brain. So, that's why we want to elevate those legs.
[00:27:26] Jill Brook: And we hear from patients occasionally who have service dogs who are trained to lie down on their abdomens to help push that back.
[00:27:34] Dr. Cathy Pederson: Absolutely. You know, another thing is if they're wearing a belt or something like that, you might loosen that belt because if it's too tight around that abdomen, that's preventing that blood flow, even if the legs are up, from getting up to the heart and to the brain the way that they want them to.
Same thing with the collar. If they're wearing a button up shirt, think about a And if you're a guy at work, right, who's maybe got that button up collar and is wearing a tie, you want to loosen those to ensure that that blood flow is getting to the brain.
You know, let them lay for a little bit. Let's get that blood flow back to the brain, but then sit up slowly. You don't want them to jump up and try to run back to work if that's what they were doing. You really want to give them time to readjust to gravity, keep that blood flow going. Of course, if they're unresponsive, if you can't wake them up, you do want to check that they're still breathing.
Check their airway to be sure that everything's okay there, but if they're breathing, if they've got a good pulse and you know that they're a regular fainter, you might just wait. If this is the first time that this has happened, you might want to call the paramedics just to be sure, get them checked out, but certainly people with POTS, you don't need to do that every time that they've fainted, right? That's quite expensive over time.
[00:28:57] Jill Brook: For sure. And I'm lucky that I eventually found medications that prevented me from fainting, but I went a few years before that, where the best thing I could do was stay chilly. And that prevented me from fainting. Sometimes I'd get surprised and I'd walk from outside into a warm building or something and bam, it would happen.
But staying cold worked pretty well for me. And the other thing that always worked well for me was Trying to minimize the amount that I'd have to pee in the middle of the night because I was pretty good at doing things during the day to prevent faints, but what started getting me was I'd wake up in the middle of the night having to go to the bathroom and then I'd wake up in the morning, you know, with blood on my head and I'd find out then that I had fainted overnight because apparently waking up in the middle of the night I'm going to pee.
I was not good at that time doing the things I needed to do. So just drinking less turned out to be a strategy. So I don't know if those help anybody, but but yeah, fainting is no fun. So, I guess a lot, a lot of symptoms from the brain just not getting enough blood flow seems like the theme so far.
[00:30:12] Dr. Cathy Pederson: Do you mind saying what medications helped? Cause that might help some other people. You said that you had some medications that helped you to faint less. Do you mind saying what those are?
[00:30:22] Jill Brook: sure. I tried a bunch of vasoconstrictive medicines.
[00:30:27] Dr. Cathy Pederson: If people haven't tried midodrine. That might be something to ask the doctor about or another vasoconstrictor if they're having a lot of trouble with fainting. Absolutely.
Good.
[00:30:38] Jill Brook: And one interesting thing is, I think in the past, my doctors have told me not to take midodrine at night to sleep, because they were worried about high blood pressure while I slept. But my current doctor is saying, go ahead and take midodrine to go to bed. And I'm not sure if, there's concerns about high blood pressure at night, but my current doctor doesn't seem to think so.
[00:30:59] Dr. Cathy Pederson: Well, if you're not fainting when you get up in the middle of the night, it might be worth it.
[00:31:03] Jill Brook: Mm hmm.
[00:31:04] Dr. Cathy Pederson: Sometimes it's a balancing act, too. Which symptom is worse? Which is potentially worse for your health?
[00:31:11] Jill Brook: Mm hmm.
[00:31:12] Dr. Cathy Pederson: and hitting your head might be worse.
[00:31:15] Jill Brook: hmm. Okay, so let's move on to a new symptom. Nausea. What's going on there?
[00:31:23] Dr. Cathy Pederson: Yeah, boy, a lot of patients with POTS really struggle with nausea. It's about 70%, 69 percent report nausea, so that's a huge one. And again, it comes back to that autonomic nervous system, and we know that this is problematic in people that have POTS. And the sympathetic nervous system, which is your fight, flight, or freeze response
innervates,
a huge Old part of the nervous system that's called the enteric nervous system, which is found in your gut.
So I think you mentioned the gut nervous system earlier. The technical name of that is the enteric nervous system. But there's a connection between sort of the brain and the enteric nervous system, which comes through the sympathetic nervous system. And this controls a variety of things like the sphincters that we have at both ends of the stomach. So a sphincter is a circular muscle that's going to open to allow food to move through and then it closes to keep the stomach contents where they should be. We have other
sphincters
at the intestines as well. But the sympathetic nervous system helps us to Know when to open and close those. It also helps us to control the mucosa, the inner lining of the stomach and intestines. And so we actually have ridges that develop in there, and we can extend those or flatten those out depending on what's going on. And those increase the surface area to allow us to be able to absorb more nutrients, particularly in the intestines.
So, often what we see in POTS is that there's a denervation of the stomach, that the sympathetic nervous system just doesn't have as much influence as it should, or as it does in people that don't have POTS, and that that can lead to some abnormal electrical activity in the enteric nervous system, which could be implicated in nausea.
So notice all the woulds, coulds, we may be going on there, right? There's a lot of hypothesizing that's going on there. But the idea is, if that sympathetic nervous system is not working correctly in POTS, That we may have uncoordinated activity in the GI tract, right? The sphincters aren't opening when they should.
The movement of food through the GI tract is not going the way that it should. It may be too slow. We talk about gastroparesis. It may be too fast. We talk about rapid gastric Emptying, but it's not right, and both of those can cause nausea and vomiting and all kinds of problems.
And so for folks that have this problem, it often tends to come after they've eaten, right? That they become more symptomatic. And so, yeah, I don't know that we've got the science 100 percent worked out here, but this is definitely a big problem for a lot of folks.
[00:34:31] Jill Brook: Yeah, yeah, and a couple interesting little tidbits come to my mind. One is that there was one study done by, I think, Cyndia Shabao's lab at Vanderbilt looking at the gut microbiome of POTS patients, and they found a couple little things that were different from normal, but they did not find anything grossly off.
And so that would have been probably one hypothesis. I know that in ME CFS, they find that the gut microbiome apparently is disturbed in a lot of patients and so that could be a reason for nausea. But they didn't find that at least in this one study with the POTS patients so it does kind of seem like there's a lot going wrong with POTS digestion and so nausea just doesn't sound that surprising.
[00:35:18] Dr. Cathy Pederson: right, unfortunately.
[00:35:20] Jill Brook: Okay. Well, speaking of Dr. Shabao's research patients feeling worse after eating especially high carbohydrates. Can you talk about that?
[00:35:30] Dr. Cathy Pederson: Yeah, so another thing that could be contributing here is blood flow to the intestine. So I've moved away from blood flow to the brain. Now we're talking about blood flow really to the abdominal organs. And so we know that there's a big increase in blood flow to the intestines in particular, but a lot of abdominal organs after a meal, right?
That makes sense because we want to digest that and then we need blood flow there to be able to pick up and absorb those nutrients. And so we have the release of hormones from our gut that are increasing the blood flow to these areas. But it's also sort of holding the blood flow in what's called the splanchnic. vascular bed, the splanchnic vascular bed. And essentially, these are the the blood flow for all of the abdominal organs. So like the stomach, your intestines, but also the pancreas, the liver, and the spleen. Right? So that the blood flow will come in. Now what's interesting is, even without eating, about one third of your total blood volume is in this splanchnic vascular blood.
It's in the Abdomen. And so that's about 25 percent of your cardiac output. 25 percent of all the blood leaving your heart per minute is ending up in the abdomen. That's a larger reserve of blood than we find even in your arms and legs. So it's a lot. Now here's the thing that relates to eating.
So even without the meal, we've got lots of blood in this area. A standard meal increases the blood flow. So when we eat that meal, we have a rush of blood going to the abdomen, going to these abdominal organs. So that's one thing. A second thing that they found is that there are lots of arteries that come off of the aorta in the abdomen, so that it's called the abdominal aorta, and one of those is called the superior mesenteric artery, and so this artery goes to these mesenteries that are around the intestines, that are going to allow us to be able to absorb those nutrients.
And when we have the sympathetic nervous system kick up, that fight or flight or freeze response kick up, that mesenteric artery should vasoconstrict, meaning that it gets smaller, decreases blood flow into those tissues. That doesn't happen in POTS patients. So in POTS patients, when there's a sympathetic Surge, when they should get vasoconstriction, it just stays the same, right?
So we're getting too much blood now going in there. And so the study showed that POTS patients had a larger increase in blood flow through these mesenteries than controls, right? Again, if I've got more blood in the abdomen than I should, what does that mean? It means I don't have enough going to the rest of my body, particularly my brain.
We have nausea centers in our brain, right, that could also be triggered here. And so, we've got this brain blood flow problem again. So, as part of this, because we've got all of this blood in the abdomen now after this meal, particularly in POTS patients, this causes Hypotension after eating a meal.
Hypotension is, again, your blood pressure is dropping too low, which takes us all the way back to where we started, which is brain fog, dizziness, fainting, right? Particularly after a meal. So there are a couple things you can do for that, right? One is to try to not eat three really big meals. But rather have four to six smaller meals during the day.
I know you've experimented with that over time. And another thing is to try to limit the carbohydrates that you eat. Maybe eat more protein, more good fats. I don't want to talk too much about this because I'm looking at a nutritionist as I'm doing this, right? Jill can jump in there with
[00:40:03] Jill Brook: But the interesting thing is that carbohydrates, according to Dr. Shabao's research, send more blood to your abdomen than fats or proteins.
[00:40:13] Dr. Cathy Pederson: which is what you don't
want,
[00:40:16] Jill Brook: They, they would cause more vasodilation into that splanchnic region.
[00:40:22] Dr. Cathy Pederson: right.
[00:40:22] Jill Brook: So we're not just saying that to, to say, Oh, you know, give up your junky sugar just because we're being no fun.
It actually has a bigger effect on vasodilation.
[00:40:33] Dr. Cathy Pederson: That's right.
[00:40:34] Jill Brook: You know, I think that one other little trick that works for me is I like to eat laying on my stomach. I have a little bench near the dining table, and if I lay on the stomach and eat like that, it seems to make me feel a little bit better. I don't know if anyone else finds that.
[00:40:52] Dr. Cathy Pederson: That's interesting. I wonder why that is.
[00:40:55] Jill Brook: I assume it's because not as much blood can pool when my full weight is on my abdomen.
[00:41:00] Dr. Cathy Pederson: Yeah. Does it matter whether you're on your stomach or your back?
[00:41:04] Jill Brook: I'm not coordinated enough to eat on my back, so I do it on my stomach.
[00:41:09] Dr. Cathy Pederson: Yeah. So compared to sitting up or standing, that would make sense, right? Because you don't have gravity also pulling toward that abdominal region, that blood flow towards the abdominal region.
[00:41:21] Jill Brook: Yeah. Okay, so, that's four big symptoms that we're not entirely certain as to the exact mechanism of action, but a lot of Good, strong theories and a lot having to do with blood flow. I'm excited to do this with other symptoms in the future. Can we have you come back and talk about other symptoms sometime soon?
[00:41:45] Dr. Cathy Pederson: Yeah, absolutely. I think, you know, just sort of understanding what might be going on can help people to think about what to look for. Oh, is there a trigger for why I faint? Or, oh, is there, like the carbohydrates, is that the reason why I'm having all this nausea or fainting after I eat? I notice my fainting is much worse.
So, I think these are really helpful. Even if the science isn't 100 percent worked out, the more you know, hopefully the better you can control some of these symptoms. Yes, I would love to do that.
[00:42:18] Jill Brook: Yay! Wonderful! Well, Dr. Pederson, thank you so much for explaining these things to us today and always. You are just an amazing teacher. I think that we all have a slightly easier time dealing with symptoms when we can understand them a little bit and know that they're real and that whether or not we have identified the exact mechanism of action, it's not all in our head.
So thanks a million. This has been fantastic.
[00:42:46] Dr. Cathy Pederson: I enjoyed it. Thank you.
[00:42:48] Jill Brook: Okay listeners, that's all for today, but thank you for listening. Remember you're not alone, and please join us again soon.
