Hydration Status in POTS and Orthostatic Intolerance
WARNING: This article is not just saying “drink more water and you will be fine”. If you hear that from me, I apologize. Also, I have plenty of patients who cannot tolerate particular components, so feel free to read and move on if you don’t think this advice is right for you. In addition, if I am your doctor we should discuss caveats or anything in here that disagrees with other advice you’ve been given. ALWAYS defer to your treating providers who have met you and know you best compared to general advice on a website.
One of the most difficult tasks in managing orthostatic intolerance with tachycardia (conditions like POTS) is optimizing hydration status. In this guide I will try to give as much clarity as I can on what I’ve learned from the literature, my colleagues, and my patients.
“Hydration status” is extraordinarily complex. Even if the question is simplified to how much water is in the body, one should consider volume of urine, amount of water lost in sweat and through breathing, and consistency and amount of poop. When one considers where the fluid in the body goes, there is fluid in the tissues, the arteries, and the veins, which is driven by various pressures around the blood vessels, how the heart pump is functioning, “resistance” through the blood vessels as they expand and contract, and salt and protein in the blood vessels and tissues which “pull” fluid this way and that. Entire textbooks are written on this from the view of edema where too much fluid gets into the tissues rather than staying in the blood vessels. However, this level of complexity definitely does not help patients understand what measures to take to improve their symptoms. It is important to understand that food (as protein/salt concentration play a role and digestion shifts blood flow to the gut), exercise (which changes heart and blood vessel dynamics and changes muscle composition), and even weather play a role (since we sweat more and blood vessels dilate in hot weather) in the body’s fluid dynamics. However, this gets quickly overwhelming and does not offer specific guidance.
The most predictable ways to optimize your hydration status are threefold. 1. Adjusting water intake. 2. Adjusting salt intake. And 3. Adjusting compression wear.
How much water is enough? Because of a hundred other factors alluded to above, the answer to this is variable. There are many different recommendations one can find such as 8 glasses per day, or two bottles of water per day, each guided by some or another study on some small group of patients or healthy controls. In my patients with orthostatic intolerance, these recommendations are almost always insufficient. Most of my genetics colleagues have been recommending 100 oz of water when someone has questions of Ehlers Danlos Syndrome (with or without genetic markers). However, because every patient has different body compositions and because of the hundred other variables, these numbers are averages at best, minimums at worst. I should also emphasize that all fluid is not the same. I’ve had patients try to convince me that because they drink 64 oz of coffee in a day, they probably only need a little additional water. Of course coffee, tea, soda, and most juice include chemicals that act as diuretics or even have fake sugars that steal water from the GI system or make people urinate more frequently.
I have found that my patients who have Long-COVID and Orthostatic Intolerance, after aggressive measures to optimize hydration status, discover that somewhere between 100-300 oz of water works for them. If I had to further average them, I would say around 150oz of water could be an average, but there is no obvious predictability to it. It is important to increase slowly and to try to be as consistent as possible. I recommend patients get at least 3 large water bottles with markings that help them keep track. My patients tend to do best with either 32 oz water bottles or 64 oz water bottles and I recommend only increasing daily intake by a maximum of 32 oz per week since it can take 3-4 days for the body to reach a steady state. Later, I will discuss keeping track of progress, but with water it is important to go slowly since sudden shifting of water in the body can cause major problems without appropriate amounts of salt and without giving time for the body to get used to the water intake increase. People have died from making these sorts of interventions too quickly, like going from a state of dehydration to drinking gallons of water, which can lead to salt quickly shifting out of the brain and leading to confusion, paralysis, or death.
The best way to prevent this is to make sure there is enough salt added at the same time. Now, I understand this will break every rule you’ve ever heard about health, but most of my patients need a lot more salt than they get, and I mean a LOT. So let’s address the medical elephant in the room. Your doctors and every public service announcement you’ve ever heard have talked about avoiding salt. “Salt is bad for the heart, it raises blood pressure, and increases risk of heart attack and stroke,” they say. “You should never add salt to your food,” they say. And if your problem is being a 55 year old man with heart disease, they would be right. In reality, most of my patients have low blood pressure. Additionally, even for hypertensive patients only about ⅓ seem to be salt responders (lowering BP by eliminating salt or raising BP by increasing salt). It is a pretty immediate response as well, so a simple way to reduce your worry about salt would be to check blood pressure before and after adding some salt. As long as the blood pressure doesn’t become a lot higher, you don’t have a primary hypertensive disorder. In fact, I will leave you to consider why the medical field has paid a lot of attention to the salt needs of 55 year old hypertensive men while not giving similar research funding and advice to younger women who faint or get dizzy every time they stand up.
So how much salt is needed, and how should it be taken? The best literature comes from for-profit companies trying to sell their electrolyte powders to patients with orthostatic intolerance, and so we need to take their data with a grain of… salt. However, having reviewed it, it does seem to match my patients’ experiences. The companies who gathered this data all have the same general ratios of sodium, potassium, and magnesium. The company most popularized in this community is LMNT (either pronounced by reading the letters or pronounced like Element). They have 1 gram of sodium, 200 milligrams of potassium, and around 60 milligrams of magnesium. Other popularized brands are Nuun (2 tabs are similar to one packet of LMNT) and SALTT (equal to one packet of LMNT). In general, one “LMNT equivalent” is needed for each 60-100 oz of water (so every 2nd or 3rd 32 oz bottle). Many of my patients mix their own (½ teaspoon [the small one not tablespoon which is the big one] of table salt and ¼ teaspoon of light salt for the potassium), and because salt water is not as tasty as they would want, they either add it to a cup of juice or a smoothie instead of the water. Others find the salt water to be more palatable if they add a squeeze of Lime or cut up fruit like they do at fancy hotels. Some people use flavorings, but it is important to consider the effects of sugar and (often much worse) non-sugar sweeteners. Make it however is most tolerable, but use your best judgement not to do anything that will make it counterproductive by adding unhealthy things.
The last component of hydration status that is often required is compression. Most patients will have been told this, tried compression socks, and given up on the whole endeavor. Or maybe they continue to wear compression socks to be good and obedient patients, but they know on a deep level that the socks don’t help (and they are difficult to put on!). In my experience, they are right. First, though, I should be clear about why compression matters. When patients lay flat, they feel better because it is easier for the heart to pump blood to the brain without that pesky gravity getting in the way. When we stand, there is a large amount of force pulling that water down into the lower body. In an ideal state, this is no problem. The blood vessels in the lower extremity quickly contract, the heart pumps more aggressively, the blood vessels in the brain dilate, and there is no change to blood flow in the brain. In POTS, all of those mechanisms are less robust and this leads to both an immediate feeling of lightheadedness and significant stress on the autonomic nervous system as it tries to keep you from fainting. No one mechanism is at fault, and so no one mechanism can be used to measure POTS. There are abnormalities in pulse rate, sometimes blood pressure (measured in the arm), and these do not necessarily correlate with blood flow to the brain. More important is the blood vessel diameter in brain arteries, which is mostly driven by the brain itself. We cannot just dilate brain arteries without dilating arteries elsewhere, but we can artificially constrict blood vessels in the rest of the body with compressive garments.
Now, I have found in my patients that socks are about worthless. They do help lower extremity swelling, but for orthostatic intolerance we need to compress larger areas. Somewhere between the mid-torso and mid thigh is typically the most useful. However, which of these areas are most important depends on many factors and it cannot be predicted. Just as one must experiment with slowly increasing water and salt, choosing compressive garments does involve a bit of trial and error. I have had patients who didn’t seem to benefit at all from stockings or bike shorts but had significant benefit from abdominal binders. Others find the only area that helps is the pelvis and bike shorts are the most useful component. Others find a combination of compressive shorts and torso compression to be the most useful. Rarely, I have met patients where the compression socks also help, but they are worth a try when working on optimization. Patients often ask me where to start and I am at a loss. There are a hundred brands and the pressures they describe seem to be so variable that my patients often have to try at least 3-4 before they feel they have optimal support. There is also the common complaint of skin sensitivity, and I have had patients who tried 10 or more brands before they could even find something they tolerate. It is reasonable to order them from somewhere that will allow returns if the garments are either not tolerated or seem to not help.
So the last bit of advice I have is about monitoring. Many of my patients are very comfortable monitoring symptoms either immediate (what happens when they stand up) or cumulative (I get exhausted by 4pm instead of by 1pm). However, some of my patients need something a bit more tangible. For them, heart rate and blood pressure are good markers. The pattern for heart rate and blood pressure from laying down to standing up in most of my patients can best be seen with a simple (however somewhat onerous) test called the NASA Lean test. Click on THIS LINK to find a form with instructions. In older patients who are dehydrated, the pattern is called Orthostatic Hypotension, and these people have a drop in blood pressure (usually 20 points in systolic, the top number, or 10 points in diastolic, the bottom number) or a spike in the heart rate (usually an increase in 30 points) within the first 3 minutes. In my patients with POTS or autonomic instability, they typically have a smaller increase in heart rate within a few minutes of standing, but around 5-8 minutes later the heart rate goes much higher (over 30 points) and then at around 10 minutes they will often have a drop in BP. This will be different at different times of day and often different after a meal, so tracking should consider this. Often, my patients will wait until mid-day, right before a meal as a good time to do the test. Lastly, if there aren’t big variations in BP, future testing can just be tracking the pulse. However, especially when adding salt, it is a good idea to keep track of BP during any symptoms just to make sure the BP isn’t jumping too high.
So… what does this look like?
Self-administer the NASA lean test. If HR increases by more than 30 points within 10 minutes, increasing water, salt, or compression is likely necessary. If HR increases by 20 points or more within 10 minutes, you may still consider escalating water, salt, or compressive wear. I tend to recommend increasing water first in 32 oz increments. Wait at least 3 days to one week after an adjustment and repeat the test under similar conditions (just before a mid day meal). If there is no improvement, repeat one more time. If there is again no improvement, it is ok to go back down to where the last point of improvement was and to try something different. For every 2-3 times you increase water by 32 oz, consider increasing electrolytes (1 LMNT equivalent) as the next trial instead of just water. On average, patients start to notice a major difference between 100-150oz of water and 1-2 LMNT equivalents of electrolytes daily. Some continue to improve up to 300oz of water and 4 LMNT equivalents but if improvement stops, either with HR or symptom management tracking, increases can be harmful. Just like medicine, it is important with hydration status to be on the lowest dose that gives the most benefit. With hydration, more is usually better, but not always better.
It is ideal to do all of this before trying to optimize medications that affect BP and pulse (beta blockers like propranolol, metoprolol, and nadolol, ivabradine, stimulants, SNRI medicines like venlafaxine, duloxetine, and desvenlafaxine, more classic treatments like fludricortisone and midodrine, and more recently utilized agents like mestinon and low dose naltrexone) but remember, most patients do require medications as well. The reason to try hydration optimization first is that without optimal hydration, the medications are often less effective and less well tolerated. Propranolol, for example, which is a great option for POTS in patients who also have migraine, was recently shown to be very effective up to 20mg twice daily but poorly tolerated at higher more effective doses. I have absolutely found this to be true in my patients, but with aggressive hydration management, they continue to tolerate and benefit further at up to 160mg per day.
So keep track, hydrate, salt, compress, and good luck!
Hydration Management Step-By-Step Low Down and Dirty - the order of the steps doesn’t matter, but going stepwise and monitoring does!
Self administer NASA Lean test
Blood pressure drops by >20/10mmHg in first 3 minutes: Indicative of Orthostatic Hypotension - may improve with increased hydration alone
HR increases by 30 bpm without above BP drop - autonomic instability - Increase water, electrolytes, and/or compression and meds likely necessary
HR increases by 20-30 bpm without above BP drop: Consider increasing water, electrolytes, or compression but may already be optimized
Increase water
Increase by up to 32oz per week
Reperform NASA Lean test weekly to monitor progress
Alternate with electrolyte increases (every other or every 2 weeks)
Increase electrolytes
Increase by roughly “1 LMNT equivalent (1000mg sodium, 200mg potassium, 60mg magnesium)” per 64oz water
Sodium most important electrolyte for hydration adjustments - can also do 500mg (about ¼ teaspoon table salt) per 32oz water
Increase by up to 1 LMNT packet per week
Monitor progress with NASA Lean test
Monitor BP - if regularly > 130/80mmHg when sitting at rest for at least 5 minutes decrease back to last salt level and consult physician
Increase compression
High waisted bike shorts (ideally up to rib cage) a good starting point
Can try medical compression wear, compression, active, and shapewear (40-60mmHg often recommended)
If high waisted bike shorts not working try adding abdominal binder
If above not enough, try full compression stockings with abdominal binder
Try different brands and styles - find what is comfortable enough to be worn daily, all day, and help support function
Test different compression with NASA Lean test to help guide choice, try different combinations
Ex:
Week 1 - Increase water from 64oz daily, no electrolytes to 96oz daily - Nasa Lean Test shows improvement
Week 2 - 96oz water daily + 1 LMNT - Nasa Lean Test shows improvement
Week 3 - 96oz water daily + 1 LMNT + high waisted bike shorts - Nasa Lean Test shows improvement
Week 4 - 128oz water daily + 1 LMNT + high waisted bike shorts - Nasa Lean Test shows improvement
Week 5 - 128oz water daily + 2 LMNT + high waisted bike shorts - NASA Lean test no longer showing improvement = stop here and discuss medication options
