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Thirsty People Feel More Pain

Bifurcati writes "Being thirsty makes you more sensitive to pain, according to a recent study. By simultaneously doing brain scans, new areas of the brain were activated when both pain and thirst were present, apparently making the pain more "painful" - perhaps a survival method so that pain is prioritized over thirst. They'd like to do more research, but ethical issues make it tough - even these subjects had to spend three hours being poked and prodded!"

26 of 273 comments (clear)

  1. what about pleasure? by Douglas+Simmons · · Score: 3, Interesting

    If not drinking water amplifies pain, wouldn't the same be true from a not-so-distant-cousin, pleasure?

    1. Re:what about pleasure? by Tony+Hoyle · · Score: 1, Interesting

      I know you're joking... but that's rather a myth. If two relatives have children then there is an increased risk of abnormality, but it isn't certain at all.

      Interestingly this has been studied in communities that marry within families a lot, and found that after the second generation the risk diminishes (for some reason a geneticist could probably explain only with lots of hand waving).

    2. Re:what about pleasure? by Daniel+Dvorkin · · Score: 2, Interesting

      No hand-waving needed: the kids born with the really serious abnormalities die off before they have a chance to reproduce. It only takes a couple of generations of that sort of selective pressure to eliminate the seriously bad alleles, or at least reduce their occurrence to the level found in the general population.

      --
      The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
    3. Re:what about pleasure? by Retric · · Score: 2, Interesting

      In the first generation you would see more "uncommon" and recessive DNA show up. Chances are if it's not the "common" DNA then it's bad mojo.

      However, in the second generation your dealing with a smaller pool of DNA so if nothing killed of the first generation then the second generation probably got a little lucky and skipped out of most of the "bad" DNA so while you don't have a lot of diversity there are fewer things "hiding in the back of the closet" as it where. Over time inbreeding is bad, but 3 or 4 generations is not going to produce people with flippers...

      Well, most of the time. One of the reasons animal breeders tend to use highly related offspring is so they can focuses on eliminating things they don't like or promoting things they like. Say you take 10 random dog's and pair them up producing 60 new dogs dogs per pair. Now select the 10 dogs with say the longest tail and bread them over time you end up with a small set of DNA that happens to have long tails and a host of other problems. But if you separate them into 5 groups you can focus on promoting long tails in each set and then cross bread at a latter time to remove any problem DNA in your line. (The fresh blood idea. You don't want a bunch of clones you want a bunch of random DNA with some specific change.)

    4. Re:what about pleasure? by TWooster · · Score: 2, Interesting

      I know you're being witty, but, to modify the saying: causation != amplification, and thus your argument (however intended to be humourous) is falacious.

      I didn't RTFA, but from the summary, I'd assume that the effects measured were mainly on the psychological side, rather than the physiological side. That is to say, I'm not sure whether or not the nerve endings were hyper-sensitive due to dehydration, or a change in the chemicals in the brain (which I'm terming here as psychological) affected the pain amplification.

      If it's physiological, it's a relatively easy leap to make to assume that pleasure would be amplified as well. If it's psychological, it's slightly tougher, but the case could still be made.

      It makes sense in the grand scheme of things, what with the experiences people have when fasting.

  2. This might be true. by CyricZ · · Score: 3, Interesting

    I used to work with a fellow named Mike. He suffered from severe carpal tunnel syndrome, perhaps caused by the decades of typing he had done while programming. He would always drink massive amounts of water and juice while working, saying that it helped his wrists. We'd make fun of him because he had to piss every half hour, but perhaps he was on to something.

    --
    Cyric Zndovzny at your service.
    1. Re:This might be true. by rolfwind · · Score: 2, Interesting
      He would always drink massive amounts of water and juice while working, saying that it helped his wrists. We'd make fun of him because he had to piss every half hour, but perhaps he was on to something.


      It sounds like he may have diabetes II. Especially if he's drinking a lot of juice (this is sugar water for blood sugar purposes).

      If you're still see him from time to time, make sure he sees a doctor about that - I drink water all day long and have to visit the bathroom maybe every 4 hours.

      It could also be an enlarged prostrate..... anyway, the bladder is capable of stretching to several liters....

      http://en.wikipedia.org/wiki/Urinary_bladder
    2. Re:This might be true. by crache · · Score: 2, Interesting

      I once too used to carry around a gallon jug and drink out of it all day. You were probably doing manual labor though and a much higher percent is released through sweat. Now that I sit in front of the computer at home I usually drink 2 glasses of water at a time and have to go to the bathroom a lot of times in a day. I'm not sure how much I'm drinking total, but I'm going to the bathroom a lot more than once every 4 hours, and I know for sure it's not because my bladder isn't up to it. Sometimes I will go without leaving the room, fill a 1 liter moxie bottle, dump it out the window and then relieve myself some more. (There's snow out there right now so don't worry about it).

  3. Ethics by pclminion · · Score: 2, Interesting

    Why would it be unethical if the test subjects were made fully aware of what was to be done to them, and were willing to undergo the experiment? Unless somebody was deceived or coerced I don't see how ethics would even come into it.

    1. Re:Ethics by fafalone · · Score: 4, Interesting

      You wouldn't even make it to getting people to consent to something like that because no institutional review board would ever approve it. It's considered unethical regardless of their consent, for so many reasons anyone with any experience in a field that researched on humans should be aware of. And furthermore it's alot easier to get permission to conduct a study with deception, as long as its not deception that's going to really harm them.

    2. Re:Ethics by weisen · · Score: 2, Interesting

      I didn't see the specific "ethically difficult" tasks that they were proposing, but pain research that involves *causing* physical pain *is* done and IRB approved. One way to cause moderate pain without physical damage is to inject capsaicin (the heat inducing oil in chili peppers) under the skin. In the article's description of the ethical difficulties, the problems cited (radiopharmaceuticals, plastic facial mask, IV lines) are somewhat specific to PET scanning and wouldn't be experienced in an fMRI setting.

      If you're bored, go to http://www.pubmed.gov/ and search for "coghill" and "pain" and you'll see one researcher's body of work.

      Some of this was funded by the US National Institute for Dental Research (part of NIH), which I always found amusing.

  4. Okay... and? by TubeSteak · · Score: 4, Interesting
    Previous studies in rats have shown that mild thirst makes the animals feel more pain but severe dehydration actually dulls pain, he says.
    So basically, what they're saying is that dehydration & pain follow a curve of some type and that curve peaks relatively early on.

    Their conclusion: Be hydrated.
    --
    [Fuck Beta]
    o0t!
  5. Pain coming from fear? by dada21 · · Score: 4, Interesting

    I am one of the least sensitive-to-pain people you'll ever meet. I used to always feel pain, because I was afraid of feeling pain. But I learned years ago how to ignore that fear -- avoid fearing entirely. Since then, my tolerance for pain is huge. I've broken bones, lost teeth (punch to the face in a bar) and had my share of other situations (cat bites, skateboard accidents, car accident, etc) and my tolerance to pain is impressive. I've even done major dental work without pain killers and passed kidney stones the same way.

    I don't drink a lot of fluids. I should (considering the kidney stones), but I don't. I love water, just don't drink a lot of it. I love tea, too, but forget to drink it.

    I think feeling pain is often a mind over matter kind of thing. I had a carpenter friend who cut two of his fingers off and didn't feel pain until he noticed it. I had a friend who broke a foot snowboarding and didn't feel pain until he looked at it.

    Have there been studies on pain and mind-over-matter situations?

    1. Re:Pain coming from fear? by JoeShmoe950 · · Score: 2, Interesting

      I must agree. I've always had a major fear of needles, and thus even a simple shot has always hurt for me, yet once I cut my finger open (somewhat deeply) after I thought it would be clever to hit a sheet of plexiglass with a sledgehammer (which exploded and cut me open), and this barely hurt at all, simply because it was unexpected, however stupidily.

    2. Re:Pain coming from fear? by Cobralisk · · Score: 3, Interesting

      I don't know about studies, but I think adrenaline is a great pain-killer. I broke my ankle playing basketball. My foot kept falling off the gas pedal on the drive home. I didn't feel any pain until I sat on the couch at home and put ice on it. It quickly became excruciating. I can think of several other similar abeit less severe experiences in my life as well.

      It could be that in moments of extreme pain the brain quickly releases endorphins to dull the pain so you can focus on the task at hand of, say, running away from a mountain lion while bleeding from the neck. But when the danger is gone the brain really lets you have it so you remember not to go stealing dinner from the nice kitty again. We do feel pain for a reason, but too much or too little or at inapproriate times is almost always bad in the long run (it sucks losing teeth, fingers, or eyes).

      --
      Waiting for ad.doubleclick.net...
  6. Flawed Logic by NoData · · Score: 2, Interesting

    Fromt the article:

    Survival instinct

    He says pain is accentuated because it is more important to survival than mild thirst.

    "The sensation with the most immediate implications for survival is pushed to the forefront of attention," he said.

    Dr Farrell says the findings suggest it could be wise for people who are about to go through a painful experience should drink more water beforehand.

    He says evidence from different types of studies also support this relationship between drinking water and pain.

    But could people deliberately use dehydration to maximise pain, say via torture?

    "We suspect if they got dehydrated enough that the overwhelming sense of thirst would probably make pain less rather than more," he said.

    Previous studies in rats have shown that mild thirst makes the animals feel more pain but severe dehydration actually dulls pain, he says.

    He says this too makes sense from the point of view of survival.

    "If you were very dehydrated it would pay to suppress pain because it might get in the way of your search for water," he said.


    Wouldn't that imply that the more hydrated you are, the more salient the pain should be, because then thirst is particularly irrelevant to your current needs? They say that "mild thirst" is not as pressing a survival need as experienced pain--well then, wouldn't NO thirst be even less pressing than the pain? I don't get it. They predict the situation switches for severe dehydration which makes sense (the thirst is more salient than the pain) but they don't explain why the pain should be more salient for mild thirst as compared to slaked thirst.

    I would guess the logic in the actual PNAS paper is better. Perhaps it's the reporting here that's got something screwy.

  7. that's funny.... by Nihilanth · · Score: 4, Interesting

    we just learned this today in anatomy and physiology. It didn't seem like ground-breaking science, just common sense. If you're thirsty, neurons in the pre-optic nucleus are shrinking (crenating) because your plasma fluid compartment is drying up. This creates a hypertonic (or hyperosmotic) environment that literally sucks the water out of your cells. Since your plasma is more concentrated (or has a higher osmolarity), the resting membrane potential goes up because the crenation of your nervous cells causes chemically-operated protein channels to open when they otherwise wouldn't be. This happens all over your body, not just in the pre-optic nucleus (also called the supra-optic nucleus). The crenation at that location (right near where the optic nerves cross eachother) causes those particular cells to pump more Anti-Diuretic Hormone through the pituitary gland, causing your urine volume to decrease (by causing the nephron tubules in your kidneys to reabsorb more water instead of making urine with it), but the same thing happens to cells all over your body when your plasma becomes too concentrated (too dry). In lab today, I had to drink 80ml of water with 7g of NaCl in it, and my feet would fall asleep whenever I stood on them for more than a few minutes. Oh, and I was thirsty and sensitive to pain. Hooray for science!

  8. Hospice Experiences by heresyoftruth · · Score: 2, Interesting

    I think this is an interesting study. When I nurse, I work hospice. When people are close to death they often tell us to allow them to become dehydrated because it decreases pain sensations. I am curious how this information fits into that.

    Of course, we get orders to pump enough morphine into them that the whole thing might be considered mute.

    --
    Nothing hides evidence like a stew. -Gus Pratt
  9. Re:What are all these ethics about? by Anonymous Coward · · Score: 1, Interesting

    The basis of medical ethics is to be able to demonstrate the absence of coercion, and not having to rely on the benefit of the doubt. CYA on a grand scale.

    It's a reaction to history. A great deal of what we've learned about the human body came from abuse of slaves, the poor, prisoners, conscripts, the mentally ill, etc. Have a new brain surgery technique? Try it out first on a worthless peon. The real watershed was the world's reaction to experiments done by a certain Dr. Mengele in Germany, and gruesome shit done in the US and Soviet Union during the Cold War.

    Nowadays you can't do medical research without lots of funding and cooperation from institutions -- institutions that would rather not be associated with, say, testing risky AIDS medication on orphans living in state care.

    Does that retard progress? Absolutely. But the alternative is depravity.

  10. curiously opposite by CupBeEmpty · · Score: 2, Interesting
    I have been the victim of "heat stroke" at least once. I set out for a hike at Navajo National Monument that was deemed a "strenuous dayhike". At the time I was engaged heavily in wilderness trips in the desert conditions of NM, AZ, CO, and UT. On this trip we ednded up running out of water (that we were promised we would be able to refill by rangers) and getting seriously bonked by dehydration. This is the one and only time I have ever hallucinated. On the 8 mile return trip we started to get loopy at about mile 6. I fell into a very "sharp" bush at about mile 7 or 7.5 and did not feel any pain at all despite the fact that this bush almost left me with permanent scars. This was also very problematic because the "falling into bushes" occured VERY close to the edge of the canyon itself, but we (at the time) did not seem to care about nearly falling over the 300-500ft drop. These problems were reflected in the behavior of the entire group (I was not the only one to experience a lack of pain/conern). Lack of hydration left us with an impaired sense of judgement and an impaired ability to sense pain/danger.

    I have also been trained as a Wilderness First Responder and can tell you that at least "extremely thirsty" people have such an incredibly deranged world view that definitions of "pain" get thrown right out the window.

  11. Re:Dehydration and pain - link known for nearly 30 by hunterx11 · · Score: 3, Interesting
    +5, Informative? More like -50,000, fucking retarded batshit insane troll.

    http://www.snopes.com/medical/myths/8glasses.asp

    Drinking more water, "cures many diseases like arthritis, angina, migraines, hypertension and asthma." Sure thing, Doc. Speaking of water, have I got a bridge to sell you...

    --
    English is easier said than done.
  12. Dissassociation by Anonymous Coward · · Score: 1, Interesting

    Sociopath?

    Disassociation of pain signals with the feeling of being "hurt" is a response to intense pain, and apparently it can also be learned through training. It is not the same as people who literally feel no pain.

    Back 10-15 years ago I had cluster headaches that came about every 3 months. Cluster headaches have been described as "probably the worst pain that humans experience". The only way I could cope was to mentally disassociate the pain with the feeling of hurt. Basically I would mentally take myself to another place and watch myself feel pain as an outside observer, but not actually experience it in the first person.

    The thought process was probably something like:
    "Oh look, my body is telling me that I am in intense pain. How interesting."

    I'm not as good at it anymore since I haven't gotten headaches in over a decade, but my threshold for pain is still much higher than average. I'd like to think that doesn't make me a sociopath.

  13. Re:Witch burning in the 21st century by Copid · · Score: 4, Interesting

    There's an ocean of difference between being thought nuts and being nuts. Challenging conventional thinking practically guarantees the former, in our age of deadly conformity. However, I find no evidence for anything other than solid scientific research in his book. Dr. Batmanghelidj is certainly not alone in questioning orthodox theories about AIDS.

    As I said, it's great when somebody brings in a refreshing point of view. At the same time, when your points of view are always "refreshing" it might mean that you're just stirring up trouble to sell books (or you're simply a kook). The probability of being right given that you're unable to convince the astounding majority of experts of your case is generally not high. It happens, but I'm afraid that Dr. Batmanghelidj is not in good company on the average. Yes, he's not alone in questioning the HIV => AIDS orthodoxy, he is damn near alone, and while serious research in antiretroviral drugs has made a dent in the appearance of AIDS in HIV infected people, I'm not sure what the people who deny the link have managed to do to treat the disease.

    The fact that his Foundation chooses to make additional research available under their own banner, in addition to the several papers in independent journals, does not prove it is all hokum.

    No, certainly not. At least, not by itself. However, if you combine it with the fact that only a small portion of his work is actually published and the larger volume of it is self published, that's a little more suspect. Add to that the fact that his really controversial stuff and the work that's really central to what makes him stand out as a "scientist" is also the stuff that has never made it through peer review, and it starts smelling a little less authoritative. This is the same set of arguments creationists and other groups selling pseudoscientific nonsense tend to use. Sometimes we need to remember some of the lessons Carl Sagan taught us: But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown.

    It is not as if peer reviewed journals have a clean slate, given the continual trickle of hoax results (recently Korean Hwang Woo-Suk, Bell Labs' Henrik Schon) so I am not sure that your point is as strong as you may think.

    Knocking the peer review process generally earns you some kook points as well. What percentage of peer reviewed articles do you suppose are fraudulent? What percentage of ground breaking work (which his AIDS work certainly would be) that makes it through peer review do you think is wrong? Now compare that number with the percentage of "ground breaking" work posted by random folks on the web. There's a reason good college professors try to teach their students that "got it from the web" is second only to "heard it in a bar" as a serious academic reference.

    Dr Batmanghelidj was certainly well aware of the disinterest of industry in his findings; imagine if the popular conception that chemicals should be the universal first resort were rejected in favour of treating chronic dehydration as a first step! That his views are commercially unpalatable (like those of AIDS iconoclasts) is hardly commentary on the quality of his research.

    And then the appeal to the widespread conspiracy. Adding up the points...

    Certainly, our society does tend to over medicate. Medication is a profitable industry, too. But don't you think you'd be seeing more whistle blowers if it were all some conspiracy to keep us taking AIDS drugs? Something doesn't smell right with that assumption. Sometimes when nobody agrees with you, you're just wrong. It doesn't always mean you're a misunderstood genius or you're tearing down The Man.

    I stop to defend the man because I am tired of the sam

    --
    An interesting anagram of "BANACH TARSKI" is "BANACH TARSKI BANACH TARSKI"
  14. Re:Witch burning in the 21st century by toby · · Score: 1, Interesting
    his really controversial stuff and the work that's really central to what makes him stand out as a "scientist" is also the stuff that has never made it through peer review

    Well, first, by definition "controversial stuff" is less likely to survive review. That's how Schon got his stuff through: it looked very, very plausible; it was just not reproducible in any way (heck, it was fake). I have no doubt Dr Batmanghelidj believed his results reproducible - and from what I've read, his assertions are not only based on his own trials, but are easily tested.

    Secondly, it is odd that you would use the construction "what makes him stand out as a scientist". Is that your own phrase? It seems an odd one to use, when you are saying that he does not pass conventional criteria for accepted "standing": being published widely but not too widely - and don't, whatever you do, put any non-reviewed papers on your site or they will conclude you're a kook!

    Knocking the peer review process generally earns you some kook points as well.

    Judging by the trajectory of my post's moderation this evening, I am going to earn more kook points than karma points by citing the late Dr F.B. I'm okay with that.

    don't you think you'd be seeing more whistle blowers

    Don't you think there are very powerful mechanisms to suppress them? I read an aphorism recently along the lines, "Control a man's support and you control the man." We know that the first effective restraint on people is financial, for instance. One does not have to get fully melodramatic and invoke Lynchian Cowboy chats or late night telephone calls here.

    Sometimes when nobody agrees with you, you're just wrong.

    I'd be thrilled if somebody would investigate the possibility that he might be right about something. You don't seem at all inclined to do that. Your energy is devoted to sitting on the fence, discounting iconoclasts as kooks without a trial (on circumstance alone); and awarding "kook points" to their defenders. A harmless hobby but not very helpful.

    little more than anecdotal evidence

    I believe Dr Batmanghelidj tested his theories clinically throughout his career. However my understanding is purely based on his book; I have not read the papers.

    legions of experts are convinced that he does not

    I have not seen a single opinion that contradicts Dr Batmanghelidj on the issue of dehydration. When I said "medical answers", I meant those that concern the human body's need for water, and dehydration as an unacknowledged cause of mistreated symptoms.

    If you are referring to AIDS: What do you do when you have experts on both sides of the question? Easy! Discredit the ones whose views you don't like. Can you be certain this has not occurred on this issue? Can you be certain that you are not yourself constructing a subjective system of innuendo around this man? If you can, please explain the source of this certitude.

    As for the non-experts: You can stop one thousand people on the street and 997 of them will happily lynch you for telling them you hold an opinion about AIDS that differs from what they heard on TV. It's that kind of hot-button issue.

    I would assert to you that they are not. They have a hard time making it past rigiorous peer review because they tend to be wrong.

    I disagree.

    I put people like Batmanghelidj, Dembski, Behe, and anybody else who shuns peer review

    I have not seen any evidence that Dr Batmanghelidj "shuns peer review"! You're trying to construct your own caricature of the man that can hardly be based on the facts you've gained from his web site - as far as I know, you haven't read his books.

    They claim to be a persecuted minority when, in reality, they have more press and more clout than much of the scientific establishment.

    In the same vein: That is absurd. What clout does Dr B have? You hadn't heard of him until this post. What effect has he had on m

    --
    you had me at #!
  15. Re:Witch burning in the 21st century by ambrosine10 · · Score: 2, Interesting


    Let people assess it for themselves, try his therapies, and perhaps add to the rather impressive roster of testimonials he offers in his book!

    Bullshit. Repeat after me: the plural of anecdote is not evidence. Only controlled experimental studies can show us if any of these BS "therapies" work.

  16. Water acting like an anesthetic by Dan+Yocum · · Score: 2, Interesting

    I used to work at the Intense Pulsed Neutron Source at Argonne National Lab (IPNS) for a couple of years. While I was there ('96-98) one of the studies a post-doc did on the QENS instrument (iirc) was to study how anesthetics work. As it turns out, anesthetics enter between the walls of cells such that they recede so far from each other that the nerve senders/receptors can't make contact thus, the pain signals aren't transmitted to the brain.

    Here's a little mind experiment: imagine having 2 balloons, one inside the other. Now, blow air into the outer balloon, leaving the inner balloon the same size. The air you push into the volume between the 2 balloons is the anesthetic. The more anesthetic, the farther apart the balloon walls get from each other and the nerves lose contact with each other.

    So, it would follow that if you were to generally increase the amount of fluid in your body, the same thing would happen: the water would enter between the inner and outer cell walls such that the nerves would make less contact than normal.

    Good ole Di-Hydrogen Monoxide!