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Water drinking acutely improves orthostatic tolerance in healthy subjects (2002) (nih.gov)
121 points by pizza on Dec 23, 2021 | hide | past | favorite | 69 comments



Orthostatic tolerance, I think, means your ability to stand up without passing out. Basically drinking water means that markers of othostatic intolerance improve dramatically in healthy subjects.

https://en.wikipedia.org/wiki/Orthostatic_intolerance


I'm susceptible to dizzy spells upon standing myself. Not sure if this is an issue of orthostatic tolerance or something else. I did a little research a while back and read that this is associated with significantly higher all-cause mortality. Yay for me.

I do drink plenty of water, maybe too much even, am in good shape, and have no medical conditions of any kind. Weed greatly exacerbates this issue for me, probably from the fact that it reduces blood pressure, but this can still happen when I'm not smoking for extended periods.

Recently, I figured out a way to short circuit the onset of a dizzy spell. Hyperventilating completely nips this in the bud, likely because it increases blood pressure [1]. I'd recommend trying this technique to anyone that's otherwise healthy (I am not a doctor) and coping with this issue.

[1] https://www.ahajournals.org/doi/full/10.1161/01.HYP.00000523...


If you are lean and regularly do endurance exercise, it's a known phenomenon. It's not of any concern since it won't go to the point of passing out, it's just a curious insight into the control loop that regulates our blood pressure and heartrate and that it's possible to leave the stable area, though not to the point of divergence :)


I do a lot of climbing, am fairly lean, healthy, and have a low resting heart-rate. I've also always had the problem of nearing "blackout" occasionally if I stand up very quickly from zero physical activity - I've never actually passed out, but you have this weird sensation where your vision, balance, and in extreme cases even hearing, fades to various degrees until the pressure stabilises.

I wondered if it would be a similar effect to what happens when a pilot pulls a high-g manoeuvrer.


I have this too; mostly, you just have to train yourself to stay seated for a couple seconds after laying down.

My doctor said the way you die is peeing. You wake up at night, have to pee, make it to the bathroom before getting dizzy, keel over, and hit your head.


Another technique you can try to cut off the dizziness upon standing is flex your abdominal muscles as soon as you feel it coming on. Works 100% of the time for me. Probably works for the same reason (blood pressure), but easier than hyperventilating :)


Yep, the valsalva maneuver against a closed glottis works great for this.


During the Valsalva maneuver (i.e., exhaling against a closed glottis or bearing down as though to defecate), intrathoracic pressure increases and leads to increased arterial pressure as a result of increased afterload. It is easily done by having the patient take a deep breath, put their thumb in their mouth with closed lips, and attempt to exhale without expelling any air.


This is the most HN comment ever. Love it. Merry Christmas :)


Thanks for this suggestion, I have the same experience of lightheadedness upon standing up (very often) and will definitely be working this into a habit.


Interesting, I found that hyperventilating is actually pretty much guaranteed to cause a fainting for me. The method is to sit down as low as feasible, maybe even lie down, hyperventilate for about a minute, and then rapidly stand up. I used to do this to faint on command until I hurt myself falling on a concrete patio. Now I know this effect has a name and a possible mitigation, yay!


Very tangential, but your comment reminded me of this...

I have this weird trick where I can put the back of my tongue against the roof of my mouth, and exhale I'm a certain way that causes a whistling sound, I think where my sinuses reach my throat.

That often makes me light-headed very shortly after for some reason.


Same thing for me. I used to do it with friends when I was a teenager. Until they got the idea I was faking and let me hit the deck, expecting me to catch myself.


Try increasing your salt intake. You can test this with water + salting to taste. If you have positive results invest in salt tablets to pick up on other micronutrients you’re also missing.


That happens to me after 10m in a hot bath.


Interesting conclusion… though I wish I didn’t have to go down a rabbit hole to understand orthostatic tolerance I saw your comment too late but it’s appreciated!

It’s too bad this couldn’t be briefly explained in the abstract by the researchers. Such small efforts go a long way in making research findings more easily understood to the general public. Overly highfalutin abstracts are a bit annoying


> It’s too bad this couldn’t be briefly explained in the abstract by the researchers.

Where would you stop? It's a medical abstract that is full of terms and phrases that, for instance, my parents wouldn't understand. How long would this abstract be if aimed at a Grade 10 reading level?

I counted at least 15 medical, diagnostic or clinical trial terms that would need to be explained to the average person, but would be the correct and concise terminology for a practitioner in the field.

"Orthostatic symptoms and syncope", "severe autonomic dysfunction", "randomized, controlled, crossover fashion", "brachial blood pressure", "thoracic impedance", "blood flow velocity", "brachial artery", "middle cerebral artery", "presyncope", "supine mean blood pressure", "(P<0.01)", "stroke volume", "Cerebral blood flow regulation", "acute hemodynamic response", "cerebrovascular regulation"


On the one hand, I think you're right, it's more the job of science journalists to summarize scientific literature and communicate its significance based on research methods and potential impact.

At the same time, this goes wrong so often that you could make an argument for a 'plain English' summary of an article to help facilitate both journalists and the curious.

Presumably researchers explain their research to non-experts all the time, so this is not some unbelievable request.


I guess I kind of feel like we are barging into a conversation between scientists and doctors and demanding that they write down to our level because we are "curious" and someone linked to it from HN.

I would expect a journalist writing about this kind of article to actually be able to understand the abstract, at a minimum, or they shouldn't be writing about this.

I know I'd be annoyed if a bunch of doctors started reviewing my architecture documents and criticized me for not explaining s3 or etl or snowflake or redshift.


Some publishers do indeed try to provide a plain-language summary where possible. See Cochrane reviews, for example this one:

https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...


Where this required (package labeling on OTC medications, for example) the FDA requires that it be written at a fifth grade level.

OTOH the so-called “label” (package insert) is written for doctors and pharmacists.

I would hate it if I had to break out words like “page table”, “TLB”, “pointer swizzle”, etc when writing a paper. I have to assume the reader has some basic knowledge of the topic at hand else they are unlikely to understand what I’m talking about anyway.

You see this in the uproar over “Critical Race Theory” or a lot of the Covid misinformation sites: the basics are not misunderstood or ignored so the argument goes in strange and incomprehensible directions. The problem is deeper than a little vocabulary.


Leaflets meant for patients are to be written in lay language. Prescribing information meant for physicians aren’t. I would consider scientific literature to be the same as prescribing information as they are aimed at the scientific community and not the lay public. Science journalists perhaps are meant to fill the gap here.


Indeed but the origin of this thread was someone complaining that abstracts of technical papers aren’t written in language that anyone could understand.


The entire purpose of an abstract is for fellow experts in the field to grok the paper quickly, not for the general public to get a hand-wavy interpretation of jargon.

And quite frankly, absurd practicalities aside, there is a lot of harm in having every paper accessible to all. There’s a wide divide between papers that have been accepted to a venue vs. important theory that has been debated and accepted by a scientific community and is worth presenting to the general public. And, the general public certainly cannot tell the difference.


I had to look up 'highfalutin' to understand your comment on a general message board.


I'm young but this happens to me sometimes in the evening when I experience caffeine withdrawal.


Are you sure this is caffeine withdrawal and not a sugar crash (https://en.wikipedia.org/wiki/Reactive_hypoglycemia)?


During intermittent fasting, an hour after my morning coffee, sometimes I set a recurring hour timer and drink a full water bottle on the hour. After about the fourth or fifth hour I get this really interesting sense of being hyper alert/awake.

It’s essentially the opposite of how I felt when I used to eat lunch and would get tired/slow.

This is more doable during WFH since I wouldn’t get noticed going to the restroom so often…


A lot of water is probably not a good thing while fasting.

The easiest fasts I ever done were dry fasts. The hardest was with a lot of water.

However since I got a kidney stone after dry fasting (I have no 100% proof it's correlated but it was close to a fast and it never happened before or after) I now drink a little bit of water while fasting (something like 300 ml per day, I do several days fasts, not intermittent).


My doctor told me kidney stones are very closely associated with mild dehydration. I’ve upped my water consumption and never had another (yet).


Water is almost never bad for you, except in very large amounts.

You absolutely need to drink more water/tea than usual while fasting and this is pretty much recommended at least by most professionals is the survival sector (probably by more, but in this case I know for sure). Especially if you need to get things done; while having no food drinking is even more important.


I have never heard of dry fasting. It sounds pretty dangerous.


It’s not intense fasting, just the ‘only eat from 5-9pm’ daily type. I definitely feel better drinking water than not though, so it may vary by body type.


dehyrdation is the root of all bodily problems - Mum was always right ;)


I thought it was inflammation? Or gut bacteria?


Wouldn't be surprised if those two are exacerbated by dehydration.


I agree, thus the reason to drink water all day.


Weird to see this on the front page. I wouldn't think the average HN reader would care.

I have occasional orthostatic hypotension. For some reason it mostly only happens after I get out of my car. I'll get halfway across the parking lot and then it hits. I've never gone down from it, but come awfully close. It helps to contract my leg and core muscles.


@pizza I am curious about the context in which you found this interesting, given this is a publication from 2002.

Being able to stand for long hours, or being able to stand up from a sitting or a supine position (without passing) is a difficulty that some in my immediate family has to deal with. The 'healthy subject' precondition does limit the scope somewhat. Regardless, just from empirical and anecdotal observations, enough water and right electrolyte balance does help.


I always have the feeling that old research articles like these on top of hn are the result of a disagreement between two individuals and one is right and rubbing it in in a public fashion


My mom is suffering from a lot of knee pain. Recently we went on a long drive and the following day her knees were swollen up like canteloupes.. it makes me sad how much she is unable to go on her daily walks, or go on hikes with the rest of the family, or even struggle to stand up from my couch which is particularly low to the ground. So I heard that she might have a circulation issue, something I suspect might be a bit wonky in myself as well. So last night I just googled “circulation changes due to drinking water” as kind of a hail mary and, lo and behold, found this


When I was in the army 23 years ago (ouch!), when there were some kind of speeches or other events where we were supposed to stand to attention for a long time there always was 1 or 2 guys that would pass out.

It was considered normal by the hierarchy. I never understood why, and the guys weren't able to explain why neither.

Maybe we should have given them plenty of water (but then they would have run the risk of pissing themselves, choices choices :)


Most of the time it's from locking your knees, which reduces circulation a surprising amount.


This is very interesting. Even though I know nothing about this and had to google what orthostatic means, I wonder how they came up with the idea to do this study. Why drinking water? Why not roll on the bed for 10 mins before getting up? What prompted them to think water drinking would be effective?


It is interesting to seek out inventors and scientists and ask "Do you remember the spark (i.e. an idea or question) that got you started?"

The rigor of science is almost always emphasized, because the core of the scientific method is empirical validation. Still, we should not discount the creative spark that sets it in motion. What inspires and motivates people to test an idea? Not a small number of scientific theories arise from unexpected places -- patterns, connections, metaphors, even dreams.


Maybe one of them was in marching band and experienced difficulty standing at attention for long periods until they started drinking water?

Looking back, this was probably something I experienced without realizing it.



Mine always said it was the hamstring if it was a physical issue, otherwise thyroid.


Random orthostatic tolerance experience. I donated blood, then jumped on a flight the next day, didn’t drink much then worked out after arriving at the hotel.

Suffice to say struggling to see your hotel room number through tunnel vision isn’t fun.


next time add in a 15-minute hot tub stay -- - -

it's an orthostatic decathlon!


I can confirm that, always had issues of orthostatic hypotension. On days with too much coffee and not enough water it comes back (not as bad as it was when I was a kid though)


Cold water helps even more!

Fun thing to find on HN. I just cited this study in a presentation given to our local paramedics on syncope / passing out.


Wouldn't being dehydrated reduce your blood pressure -> being properly hydrated restores blood pressure.


It’s not that simple. Physiology is a very dynamic system so I appreciate any corrections. But, basically the venous system has a lot of compliance and capacitance holding 70% or so of your blood volume in a euvolemic state. You can easily maintain blood pressure and arterial volume while dehydrated.

Orthostatics refers to change in blood pressure when standing. Every time you stand up you lengthen a large column of blood that gravity wants to pull to the bottom of your feet. Pressure sensors in your neck (where blood goes to the brain) immediately tell the autonomic nervous system about the sudden drop which sends a response to increase heart rate and increase resistance in the arterial system to maintain output and arterial pressure so you don’t pass out. To accommodate this you pull extra volume from the large venous pool to continue optimally filling the heart with each stroke. If your venous pool is low, the extra refill volume and venous pressure isn’t available to keep up with the sudden demand and the arterial pressure drops.

We have different medication classes that can selectively slow the heart down or decrease blood pressure by preventing increased resistance in the arterial system and those folks are also at risk of orthostatic hypotension because of blocking those compensatory mechanisms.


It's the study that laid the groundwork for /r/hydrohomies


Can this help jet fighter pilots and F1 drivers?


interestingly when people faint they are usually given water


"ingested 500 mL and 50 mL of mineral water "

Try drinking water with a bit of salt dissolved in it (sole water some call it), best prepared using rock or sea salt which is richer in minerals than refined tabled salt. (The categorical fear of sodium is very simplistic; it's the ratio of water to sodium that matters.) Distilled water can flush electrolytes from your body which is not what you want.


>Distilled water can flush electrolytes from your body which is not what you want.

This could be a good thing, like for people with hyperkalemia and hypernatremia. Distilled water is usually given to patients with hypernatremia.

https://aspenjournals.onlinelibrary.wiley.com/doi/abs/10.117...

It is always best to know your body chemistry before listing to such blanket advice. (I suffer mild hyperkalemia and hypernatremia which is why I know this.)


just to clarify for the casual reader, the GP comment talked about adding salt (NaCl sodium chloride) to drinking water, and the parent comment is talking about "not for hypernatremia"

But from the root words, hypernatremia appears to be too much natrium/sodium. Presumably hyperkalemia is too much K potassium? the low sodium salt substitutes you see at the grocery are generally potassium salts.

only pointing this out because the two comments boil down to "you should add sodium to your diet" and "no, not if you have too much sodium" which somehow seems a little simpler


Do people actually drink distilled water? If you want to increase your water consumption, I believe unadulterated tap water will contain sufficient electrolytes. No need to complicate your life by supplementing with additional salt. Obviously, drinking too much tap water will deplete the electrolytes in your blood but it's probably still wise for more people to drink a little more water than they already do even if it doesn't have the perfect salt balance.


Many cities, such as Toronto where I live, still have lead pipes for drinking water. The levels are extremely low, and they have various additives in the water supply to minimize risk, but the safe level of lead consumption is zero. So yeah, I drink distilled water. It’s also handy to have distilled water around for various uses, such as steam irons.

There are many sources of electrolytes, bananas, our endless array of processed food, salt, etc. I can’t imagine anyone in North America needs to worry about their electrolytes, beyond those that do anyway due to medical issues or due to strenuous physical activity.

Our lackadaisical attitude toward pollutants in our drinking water, especially lead never ceases to amaze me. Though we shouldn’t be dumping such large amounts of a pollutant in our waterways, it is wild to see the traction fluoride gets with the paranoid.


Yes, adding to the existing comment, all water I use in the kitchen for internal consumption comes from either an RO filtered tap or a water filter pitcher, both of which remove electrolytes. The purpose of this is to avoid lead and other contaminants.


For any person consuming a healthy balanced diet, how would distilled water flush electrolytes from their system? Their food would be providing them with plenty electrolytes, such as sodium, potassium, etc. Electrolyte supplements are unnecessary for all but more intense longer endurance exercise (same for energy bars). RO (reverse osmosis) water filtration systems are best in class - far better at removing contaminants than pitcher filters - some RO models have a calcium cartridge which is purely meant to improve taste, not save anyone from electrolyte flushing.


Do RO water systems still waste the vast majority of what comes out of the tap? I've wanted to get one, but they seem a bit environmentally gnarly.


The usual cheap RO systems operate from household water pressure only. They fill a pressure tank at the output, allowing the purified water to be dispensed from a faucet. The pressure across the membrane is that input pressure minus the tank pressure. That's relatively low, so the efficiency is poor, wasting perhaps four gallons for every gallon of pure water.

You can improve the efficiency with an electric booster pump, or with a "permeate pump" that recovers energy from the exiting waste water, or by simply filling a pitcher with no pressure tank. I'd expect that even the most wasteful systems are still a small share of a typical household's total water consumption though, assuming they're used only for drinking and cooking water.


Thanks. I suppose there may also be a way to use the excess as grey water.


Use Sodium Bicarbonate or Potassium Bicarbonate instead, it helps as antiacid as well


Note that in the US, all salt can be labeled "sea salt". Other places, like Canada, mined salt can't be.




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