Why Does Pain Tolerance Differ Among People?

dmckeever's picture

            Pain has been a topic of discussion in lecture on many occasions, perhaps because pain is something that most experience, but want to avoid. Though most experience some form of pain, incidents vary in intensity and people’s reactions are of different extremes, as well. Why? What causes these differences in pain tolerance? It was determined in class that pain is the result of certain pattern generators in the nervous system, so it is only natural that one looks to the brain to get to the root of pain tolerance. Research has been done that claims the source is genetic, psychological, or even gender-based. But in fact, this student believes that pain tolerance is the result of a combination of at least these three conditions.

            The first, and most evidentially-supported, argument—the genetic explanation—revolves around the gene that codes for COMT, an enzyme that metabolizes, or breaks down, the neurotransmitter dopamine. Dopamine delivers signals from one brain cell to another, and so can theoretically proliferate pain signals throughout the nervous system. But, COMT depletes the dopamine supply in the brain, freeing receptors in the brain to which the dopamine was bound so that they are available to bind to endorphins, which lead to pain relief (1,3)

The studies done recently on COMT deal with the common val158met polymorphism, in which methionine is substituted for valine at codon 158, causing a “three- to four-fold reduction in the activity of the COMT enzyme” (3). Two alleles code for the expression of this gene: val and met, resulting in an instance of codominance. If an individual receives a val allele from both of his/her parents, the COMT enzyme that is produces is strong, i.e. it readily metabolizes dopamine so that less pain is felt. If an individual receives the met allele from both parents, the COMT enzyme produced is weak; dopamine builds up, suppressing the body’s supply of natural painkillers, or the endogenous opioids (endorphins), so that that individual suffers from low pain tolerance. A heterozygote, receiving the val allele from one parent and the met allele from another parent, has a pain tolerance that lies somewhere in between that of  the homozygotes. In summary, the stronger the COMT, the more receptors that are freed from the grips of dopamine and so the more endorphins that are able to bind to these receptor sites and the more relief from pain that is felt (1, 3, 4).

The lead researcher on the COMT project, Dr. Zubieta, cautions that pain tolerance cannot logically be explained by a single gene, an argument supported by the fact that COMT has other functions in the body; however, COMT must play a very large part in the differences seen in individuals. This statement leads this student to look elsewhere for other explanations of ranges in pain tolerance: psychology.

The psychological research done on this topic operates under the understanding that pain can be manifested in negative emotions, such as anxiety, depression and anger, to name a few. These researchers argue that these negative emotional responses to pain stimuli can be counterbalanced by positive emotional responses; in one very compelling study, the positive emotional responses were produced by sexual fantasies. The subject was told to immerse his/her arm in ice water until he/she could no longer bear the pain. Then, the subjects were separated into three groups: one group was instructed to envision a neutral fantasy (e.g. walking); another group was instructed to envision a sexual fantasy, and the third group was not given any specific instructions. Then, each group underwent the same submersion task as before. Interestingly, those subjects that were asked to think of a sexual fantasy while experiencing pain “handled pain better and experienced less pain [than the subjects under other conditions]. They also were less anxious and depressed, and less angry.” In general, the subjects under the sexual fantasy condition were able to endure the pain for longer. The pleasant emotions produced by the thought of a sexual fantasy counteract the unpleasant thoughts that are a result of pain. The implications of this are that if a person enduring a painful experience imagines something that evokes in them positive emotions, they are able to cope with the pain better, and actually report experiencing less pain. Conversely, if a person experiences negative sensations from sources other than the painful experience in combination with the painful experience, the subject cannot endure as much pain and reports experiencing more pain than other subjects (2).

Psychology accounts for aspects of tolerance that genetics cannot: “mind over matter.” There is a possibility that two people can tolerate the same amount of pain, but that one voices their felt pain more readily than someone else. This could arguably be because one person is mentally stronger than the other. One person might feel an unbearable amount of pain, but stays quiet, does not medicate, goes on with his/her day, etc, while another person, under the same physical stress, manifests his/her pain in moaning, pill-popping, crying, being bed-ridden, etc. Maybe that person that seems stronger has conditioned him-/herself to suppress such manifestations of pain, or maybe he/she has been conditioned by society, so that this idea of “mind over matter” is actually cultural (i.e. feeling pain is a sign of weakness, and in some cultures, weakness is looked down upon more severely than in others).  This conscious suppression of reactions to pain must then involve the I-function, an aspect of the nervous system in which the genetic explanation would not be involved. But, obviously, this cannot be the only explanation for the wide ranges of pain tolerance seen across humanity. The research is quite convincing, but does not take into account the genetic explanation for pain tolerance, just as the genetic explanation does not take into account this theory. So, it leads this student to wonder to what extent pain tolerance is genetic and to what extent is it psychological? Furthermore, is anything else involved in a person’s tolerance level for painful? And in fact, this student has found some research that suggests gender has something to do with it.

Researchers have found that estrogen can act as a natural painkiller. Higher estrogen levels result in a higher pain tolerance, and lower estrogen  levels cause effectively lower pain tolerance in subjects. Granted, the study was done only in women, but it is curious that hormones can effect how one deals with pain. Though this student did not find any research that inspected estrogen levels in males, or levels of male-specific hormones like testosterone, the studies examined here open yet another door through which pain tolerance may pass. Now, one can question whether these significant changes in pain tolerance are due to estrogen levels specifically, or to hormone levels in general. Furthermore, estrogen levels change with menstruation so that a woman’s pain tolerance would, theoretically, also vacillate with changes in the body. So, though genetics and psychology may play a part, a woman’s pain tolerance is not constant, but is subject to manipulations by hormones (3, 5).

It seems that combining the knowledge gained on different theories of pain tolerance—genetic, psychological, and hormonal explanations—leads one to the conclusion that pain tolerance is an intricate neurological output. Not only is one’s basic threshold for pain determined by the presence of certain forms of a gene, but it can be pushed one way or the other by changes in hormone levels and one can conditions     him-/herself to live and work through the pain. In conclusion, this student argues that some aspects of pain tolerance are spontaneous and incontrollable; but a large part of it lies within the I-function.

      

Works Cited

(1) “Gene Controls Pain Threshold”, http://news.bbc.co.uk/1/hi/health/2784869.stm

(2) “Sexual Fantasies Increase Pain Tolerance”, http://www.hopkinsmedicine.org/press/1999/DEC99/991216.HTM

(3) “The Gene for Pain Tolerance”, http://www.bio.davidson.edu/courses/genomics/2003/talbert/pain.html

(4) “Can’t Stand the Pain? Your Genes Might Be to Blame”, http://www.med.umich.edu/opm/newspage/2003/paingene.htm

(5) “Pain and the Brain: Sex, Hormones & Genetics Affect Brain's Pain Control System, Shaping a Person's Pain Perception”

http://www.med.umich.edu/opm/newspage/2003/painbrain.htm 

Comments

Serendip Visitor's picture

Strangely high pain tolerance for trauma

Interesting, I've always had an extremely high pain tolerance, but apparently there is no underlying cause for it, I am healthy. By extremely high I mean, I've had badly broken bones and I would rate the pain somewhere like, 5? Maybe? Maybe 6-7 at times if I'm being really generous. And by badly I mean as bad as it can get pretty much, even for an open fracture. I've had a few surgeries as well, and was on zero pain meds for the minor ones. Not even Advil, it just wasnt necessary. But I have had fevers a few times when the headache was unbearable. It seems to be mainly trauma that I'm very resilient to. I'm not trying to brag or anything either, it honestly worries me a bit because as a kid I broke my arm (fairly badly) and had no clue it was broken at first and it took me a whole to even realize something was off (I thought it was just badly bruised). Then another time I broke it I wouldn't have known it was broken from pain alone, I just knew because it was literally in pieces. I'm worried because I play sports and I'm afraid that if I get a more minor injury I won't even know and then I'll make it way worse. But of course I still get period cramps and sinus headaches all the time, lucky me.

Serendip Visitorssshriniwas tonpay's picture

perception of pain ,individual variation

what I propose is the endogenous opioid peptides like dynorphines,endorphines,enkephlines areresponcible for individual variation in the susceptibility of pain,which modulate the mu kappa and delta receptors in body.the gene dependent synthesis of these endogenous opioid peptide synthesis and their concentration may be responsible for individual variation.

Serendip Visitor's picture

pain

I've read the comments and I'm disappointed at those of you who say people with a low pain threshhold are 'babies' and thay they should 'shut up'. Pain is real, it's miserable and debilitating. Until there is help for people who suffer chronic pain (ie asthmatics have inhalers, even neurological adhd has medication) then a bit of common human decency and understanding wouldn't go amiss. It's like telling a clinically depressed person to 'snap out of it'. It's pointless and damaging. As pain is in the majority neurological, it is counterproductive. As well as being nasty and lazy of course. Pain does not make the sufferer inferior to you. Sorry about that.

Serendip Visitor's picture

pain

my boyfriend cant stand any pain what so ever. he even drinks his tea cool as it hurts him and he lets his food get cold because its to painfull in his mouth if its hot, i eat the same meal and im finished well before him and i dont find my tea or food to hot, he just cant stand going to the dentists or the hospital because he feels pain so much/ he is quite good if he gets a cold or anything that isnt really painfull. he doesnt moan, he has mild tourettes syndrom i wonder if that has anything to do with it,

Serendip Visitor's picture

I think another factor

I think another factor affecting pain tolerance could be nerve damage. I have not researched it but it seems like common sense to me. If a nerve or group of nerves is damaged severely enough they will not be able to send messages to the brain alerting it to an injury.

Serendip Visitor's picture

Pain Tolerance

Hi, I think pain tolerance depends on your mental state. I had an appendisectomy, 2 abortions, and very very painful mensturation, but i never complained, although i felt immence pain, almost unbearanle. My brother on the other hand has only abdominal cramps bcz of constipation and he started moaning, crying and screaming. He always does that specially after his divorce, which is partly my mother's fault. so by showing this much pain, he actually tries to get her attention and shows that bcz of her he is suffering, as she also starts crying with him. so i think its more psychological than genetic. We both have almost same genes.
so my opnion is that people who cry and moan are actually trying to get attention or a benefit out of that pain. I totally agree with "pain" who said that THEY SHOULD STOP ACTING LIKE A BABY AND SHUT UP.

Serendip Visitor's picture

Pain

I find it odd, let me give you some examples, it's not fair to me, once when I was playing in band ( I play flute, which need a lot of air), I bend down to pick up my water bottle, and I pull a tendon in the back of my neck and for some reason that made my breathing shorter, yet I kept playing although I felt as if there was a knife slowly tearing my tendons and I don't show any sign of pain to anyone, tommorow in gym class, somebody also pulled a tendon in his neck and he started crying out loud while his tears were pouring out of his eyes, and he gets to sit out for 20 min. That's not fair. I have asthma and I have a moderate attack in gym while doing laps and I didn't have my inhaler on me and I still kept running even though I can't breathe and I can feel my heart pulsating in my eyes and brain, and I was sick that day and I didn't complain, next week, one of my friends complains about having stomach pains and he gets to go home, that not fair. I get large bruises and I'm still expected to run, jump or work, I get a big gash about 4 cm long (2 inch) on my knee and I didn't even notice it untill it was itchy and I scratched and noticed it was bleeding, and no one cares even though they get smaller injuries and cry, I don't, I get paper in my eye ( yes, I said paper) and I cry little and the damn school gives me and ice cube to put on it even though I that eye temporarily lost its vision to 20/50, everyone gets a small cut and they over exaggerate it and say I don't know what it's like, they haven't experienced true pain, they say they cant run because they are tired, or they didn't eat, half the time I am sick and my asthma just flares up under minor exercise and almost chokes my when I am running and I don't complain about the running, I even have higher endurance than some of them and there's nothing medically wrong with them, SO THEY SHOULD JUST SHUT UP AND STOP COMPLAINING AND BEING A BABY ABOUT CUTTING THEIR FINGERS OR STUBBING THEIR TOE AND BE CONSIDERATE TO THE PERSON WHO HAS ASTHMA AND BRONCHITIS.

Ryry's picture

Pain

In all honesty I have twisted my back as well as pulled a muscle in my neck. I would like to share and clarify neck pain is much, MUCH more brutal.

When i twisted my back, there was a slight click, the pain was sharp and a cramp like feeling. Overtime the muscle became very tense, warm and sore. Movement was indeed restricted but I was not disabled. It was difficult to stand without aggravating the muscle in my back, but day to day chores was indeed carried out. My back took about 3 weeks to feel normal again.

Back Pain rating - 6

On the other hand when I fell funny on my neck I heard this crunching sound on the back right side of my neck. IMMEDIATELY the pain was close to intolerable. The feelings was like someone had hold of your muscle and hyper-extending it until breaking point. I was unable to move period. The slightest movement created immense pain in my neck, a simple thing like standing up was a challenge in itself. My neck took about four weeks to return to normal, even when it was better my neck to time to hold my head up straight!

Neck pain rating - Something I would not like to experience again anytime soon.

Mingtian's picture

Hmm

"Researchers have found that estrogen can act as a natural painkiller. Higher estrogen levels result in a higher pain tolerance, and lower estrogen levels cause effectively lower pain tolerance in subjects. Granted, the study was done only in women, but it is curious that hormones can effect how one deals with pain. Though this student did not find any research that inspected estrogen levels in males, or levels of male-specific hormones like testosterone,"

I'm skeptical about the effects of estrogen on pain tolerance. Maybe it only works for women, but seeing as mens natural hormone is testosterone, I would assume that men would be exempt from the estrogen effect and instead have a testosterone effect on pain perception. Didn't find any research on men? There's plenty. http://www.bioedonline.org/news/news.cfm?art=1017

This also contradicts the face that studies show men generally have a higher pain tolerance. Both men and women(all humans actually) produce natural painkillers. Estrogen however, is more for birth/menstrual cycle, whereas testosterone is more for general life and is likely more powerful than estrogen in terms of decreasing pain.

Brandon's picture

Improper Support for your statement?

Hi Mingtian,

It is good that you suggested that there may be sex-differences in pain tolerance moderation (i.e. estrogen vs testosterone).

However, I wanted to point out that your reference was not substantial. Just to quote you below:
"Didn't find any research on men? There's plenty. http://www.bioedonline.org/news/news.cfm?art=1017"

I would like to highlight that the article makes most of its claims with reference to men (i.e. human males), however, the article cited was a study in birds. It is thus not a fair claim that testosterone will influence pain tolerance in men based on a study in birds. It may inspire human research however.

Crystal Thomas's picture

Concerned Mother

I have concerns about my four year old. She is constantly picking at her scabs or trying to pick at mine. When she starts to bleed she stops. For example she got a small cat scratch and it didn't even bleed and would have been gone in like a day but she kept picking at it to where now it is a big scar. When she get a pop on the butt she laughs. But when she gets shots she cries. How or what should I do to get her to stop picking all the time?? I need help on what to do to keep her from having scars all over her body.. Please email me if there is something that i can do or what I need to do to stop this.

Thank You,
Concerned Mom

In the Moment's picture

I have a higher tolerance for

I have a higher tolerance for pain mainly because when I experience pain, I focus on something or someone else. I feel that when I think of a situation, it counteracts the pain I am experiencing and the pain is dulled and not so intense.

BOBBIE's picture

SOME PEOPLE HAVE A HIGHER

SOME PEOPLE HAVE A HIGHER TOLERANCE FOR PAIN CUS SOME LIKE IT CUS THEY HAVE LESS NERVE PAIN ITS KIND OF IN A STATE OF BEING NUMB. NORMAL PEOPLE FEEL PAIN AND PUTTING UP WITH PAIN AFTER A LONG LENGTH OF TIME CAN AFFECT YOUR HEART, I'VE RECENTLY HAD OPEN HEART SUGERY SO THATS HOW I FOUND OUT. JUST ONE TIP TO PEOPLE WITH SO CALLED HIGH TOLERANCE, STOP BRAGGING TO THOSE OF US THAT ARE IN CHRONIC PAIN, ITS STRESSFUL AND IT MAKES US HATE YOU, AND WHEN ANYONE TELLS ME "WELL I JUST HAVE A HIGHER TOLERANCE THAN YOU DO" I TELL THEM "OK LETS HAVE SOME FUN THEN, LET ME PUT OUT SOME CIGGYS OR CIGARS OUT ON YOU, HAVE FUN WITH IT C'MON MAN" AND THEY USUALLY BACK OFF AND LEAVE ME ALONE LOL.

Susan Moore's picture

Love your comment about pain

I whole heartedly agree and I can't agree with you more, I experience people being a big pain in my ass, especially when they keep going on about how much pain they are in and in so many words are telling me I am being a big baby. I have had a lower back injury for several years now and a year ago fell into a bathtub while painting and broke off the mounted ceramic soap dish with my neck in which scan showed two bulging discs in my neck. I work, raised two sons, among other accomplishments. Kudos's to you my friend! Well put !

Anonymous's picture

For years I have wondered

For years I have wondered what is wrong with me. I am not effected by pain as my fellow peers are. There has been many instances when people have looked at me like im defying laws of human nature. Is there something wrong with me?

kathleen hill's picture

pain

i believe that u have a good handle on mind over matter....my husband can do the same thing ..ignore pain...i cannot ..it consumes me!!!

Anonymous's picture

I love pain for some reason,

I love pain for some reason, and I have a huge tolerance to it. For some reason no matter what I do I always end up with a smile when I bleed.

Anne's picture

If you do love pain and end

If you do love pain and end up with a smile on your face when you bleed, then you're just a masochist. It's actually pretty cool.

Anonymous's picture

Seek medical advice as soon

Seek medical advice as soon as you can.

Charmagne Bradley's picture

I have had several areas on

I have had several areas on my body that I am sure have been desensatized by slight electromagnetic pulse. My skin is crawling. I'm not sure if it is possible or not, but I believe nanochips, silicone chips or fiberoptics were implanted on just beneath my skin to creating continuous pain infliction operated remotely... is that possible? I have areas on my back that have boil type wounds that are severely painful and 2 raised abraisons on my right arm and shoulder. I think I may have been RFID chipped. Is that possible and I also, on many occasions feel like I've been drugged. No one is around, so I think I may have been given some sort of implant releasing drugs in my system. Is that possible?

Please email me back with conclusions if you can. I'd really appreciate the insight.

Anonymous's picture

Please see a doctor

I do believe that you suffer from some form of hallucination. You should really seek some kind of medical advice. Have you saw a doctor concerning the wound on your body.

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