Sounds Like Weird
08 September 2024
My family were always hugely into visiting mountains: hiking, skiing, and so on. We spent a good chunk of our weekends in the mountains. Catch is, at age 11, I had sudden onset altitude sickness. I would sometimes throw up. I always felt nauseated when we got above about 4,000 feet. I gasped for air before other people did.
In physical education class in ninth grade, we had to do a six-minute run walk on a particularly smoggy day. I came in second to last, only ahead of the kid with crutches. I felt like I couldn’t get enough air.
Over the years, it slowly worsened. My college required a speech class in order to graduate. I enrolled in it 7 times before I was finally able to finish. While I did have a normal human amount of fear of public speaking, most of my issue wasn’t that at all.
It was simply having to stand for five minutes.
Meanwhile, I’d already given up playing bass in a band, even though we only had one or two gigs a month, because standing for even a short gig became extraordinarily painful.
By late 2019, I was having daily migraines, and, when I caught Covid in January 2020 (being the precocious sort), my POTS symptoms got far worse. However, despite having the syndrome for decades, it still wasn’t identified.
In July, I wound up in the ER, and, as a result, I wound up on a Holter monitor for a week. Because of that, I started paying attention to my heart rate and when it was high. One morning, I was nuking water for my coffee, and I felt a little woozy. My heart rate was over 140.
This is when the light bulb went off. Before I got off the Holter, I took a walk around the block (peak heart rate: 160) and was gasping for air coming up our small hill. Then, two days later, I did it again, only with compression leggings: 140, with less gasping.
Managing the symptoms requires some understanding of what’s happening, so the next step was hitting the books.
So POTS is a syndrome, not a disease, which means there are multiple causes, but the basic one is this: when humans stand, arteries constrict to prevent blood pooling at the feet (which is called acrocyanosis).
That signaling for the arteries to constrict doesn’t work in POTS:
Norepinephrine signals the heart to beat more rapidly and forcefully, restoring normal blood flow to the brain. It also signals the blood vessels to tighten, which drives blood to return to the heart instead of pooling in the lower half of the body. Within a few seconds of standing, blood pressure is restored to normal.
However, for reasons not fully understood, this signal is ineffective in POTS, and the blood vessels do not tighten in response to norepinephrine. More blood remains in the lower body, so that less returns to the heart, and therefore less is pumped out to vital tissues and organs.
So the body’s trying to get the blood vessels to constrict and is furiously signaling with Norepinephrine, but the connection isn’t there. So the heart rate goes up and up.
As if messing with the blood return upstairs wasn’t enough, 70% of people with POTS have hypovolemia, aka too little blood volume:
Absolute hypovolemia is commonly observed in POTS, with up to 70% of patients exhibiting deficits in plasma volume and red blood cell volume (Fu et al., 2010; Raj et al., 2005; Sheldon et al., 2015; Stewart et al., 2006a). This hypovolemia can reduce [cardiac] stroke volume and lead to compensatory tachycardia to maintain cardiac output and BP.
There are probably numerous underlying causes for low plasma volume, but it’s a thing for this 70%, and it’s a problem that leads to heart rate issues. They need to add plasma volume. The fluid volume in the body is largely controlled by the kidneys, who decide how much water volume to maintain based upon how much salt is in the system. More salt? Retain more water, and suddenly you have more plasma volume, so the heart’s not working so hard to maintain cardiac output.
So adding salt will benefit these 70% more than it will the other 30%.
However, if you look at the healthy controls vs. people with POTS in this study, specifically Figure 2, Chart B, you’ll note that only a few healthy controls had significantly higher heart rate on a high sodium diet. Equally as many had as much of a lower heart rate when standing. This suggests that the guidelines for salt intake for non-POTS patients may need to be more clearly identified in subgroups so people can best choose the approach that works for their body type.
For me, my doctor and I went through all my meds and changed a couple of them, and change the timings for one of those. We also changed some of my supplements. One of those med changes caused such a dramatic shift that I could walk so much better it was obvious to people who didn’t even know me very well.
To maintain blood volume, I added a lot of salt into my diet.
The bigger question a lot of people with POTS have is this: if we can’t stand for long periods, and walking is only partly better than standing, what are the best forms of exercise?
Rowing, bicycling, and swimming/aquatics (all semi-horizontal or horizontal) are generally easiest for people with POTS, but many don’t figure that out on their own. In aquatic sports, water pressure helps minimize pooling in the lower limbs even when standing, plus it helps keep water volume in.
Photo by Denys Nevozhai on Unsplash