10 ms·
Time to redefine normal body temperature? (2020)
- seventytwo 4y agoThey didn’t directly mention it in the article, but I wonder about increases in sedentary lifestyles over that same time period. Base metabolic rate would go down as an average as sedentary lifestyles increase.
- avalys 4y agoAs the article says, Wunderlich reached a conclusion of 37C in the 1800s, and that’s what we’ve used since then. The real problem appears to be that converting to Fahrenheit and reporting this as “98.6F” suggests an order of magnitude more precision than “37C”. 36.5C would still round to 37 but corresponds to 97.7F.
- ncallaway 4y agoI thought the same, so I tried to find Wunderlich. The only source I could find (https://www.google.com/books/edition/_/3-wHAAAAIAAJ?hl=en&gbpv=1&pg=PA1&dq=1868+Carl+Wunderlich https://www.google.com/books/edition/_/3-wHAAAAIAAJ?hl=en&gb...) seems to have Wunderlich reporting "98.6F", and then converting to Celsius: > The average normal temperature of the healthy human body in its interior, or in carefully covered situations on its surface, varies, according to the plan of measurement from 98.6° to 99.5° Fahr. (37° to 37.5° C.). It is about 98.6° in the well-closed axilla, and a few tenths of a degree higher (.5-1½ or 2° Fahr., .7° Fahr. average) in the rectum and vagina. So, as far as I can tell it's not a sig-figs issue in conversion, but the actual original source that produced "98.6°". It almost seems like Wunderlich should've used 37.0° to 37.5°C to be consistent.
- Jakob 4y agoThat is a translation artifact. The German original cites 37-37.5 degrees Celsius on average: https://archive.org/details/dasverhaltender00wundgoog/page/n16/mode/1up?view=theater https://archive.org/details/dasverhaltender00wundgoog/page/n...
- deleted 4y ago[deleted]
- ncallaway 4y agoGah! Of course Wunderlich didn't write the original in English, and I should've looked for the original in German. I'm a little surprised and disappointed that the translation also translates the units, though. That seems to be stepping just outside the bounds of what I would want translated (at least, in the context of a medical journal or scientific writing). Thanks for that correction!
- antiatheist 4y agoInteresting that the original german text uses Celsius as the primary measurement, and provides conversions in Rankine. No mention of Fahrenheit. Funny that people argue over this and some guy named Wunderlich who measured a bunch of asses. Did he write that translation or is Google Books fake news?
- syrrim 4y agoIt's obviously not rankine, seeing as it gives a conversion of ~30R = ~40C. Looks like its actually Reaumur: https://en.m.wikipedia.org/wiki/R%C3%A9aumur_scale https://en.m.wikipedia.org/wiki/R%C3%A9aumur_scale
- antiatheist 4y agoWell the more you learn, thanks. Actually makes it even more interesting, Wunderlich and his reaming to get some Reaumurs. What were his actual measurements taken in and how accurate was his thermometer? And who's vaginas has it been in? Curious I get flagged for pointing out the potential measurement inaccuracies and the errs of scientific reproducibility, all while having some humor.
- lynx23 4y agoI have always been taught that 37C is the upper limit, actually bordering on fever. So 36.5C or even a bit lower was always considered healthy and fine.
- FullMetalBitch 4y agoSame here, 36-37 normal, over 37 fever.
- tasuki 4y agoSame here, but I've since readjusted :) Currently the top comment says "Basically, in our experience, anything below 38.4 °C could just as well be caused by any of a number of non-fever conditions at something like a 90 % confidence level" ... which is panicky territory for me. But anything under 38 is fine.
- lynx23 4y agoWell, if I have anything above 37.5C, I definitely feel ill. If you call that fever, or something else, feels hypocritical to me. Luckily, this stuff is a continuum. Still remember the 40.6C as a child, as my sense of equilibrium completely went bonkers and I start to hallucinate.
- gpvos 4y agoI was brought up with everything under 38 being subfebrile (Dutch "verhoging") which means to watch out, but no need to call the doctor yet.
- lynx23 4y agoI wouldn't call a doctor as long as I am below 40C, but thats maybe just me not wanting to uselessly overload the system... Other people seem to have different attitudes. Come to think of it, our local media just had an article saying doctors are asking patients to not come to the doctors office just because they have a little fever. A similar thing seems to happen in children ambulances. Doctors tell me that 90% of the cases there are just clogging the system and making it harder to find the 10% which really need immediate help.
- asats 4y agoNot sure if it's all the countries, but I have always heard the normal body temperature in Celsius stated as 36.5, which is 97.7 F. Is 98.6 an american-only thing?
- thrdbndndn 4y agoIn my country is more like: Normally you should be 36.x; 37 would be a little bit high but not yet fever. I personally think it really isn't that important though, because how people measure it is way more imprecise/fluctuant than the standard itself.
- defrost 4y agoWe (Australia) have always in my experience taught and been taught a range. eg: > You probably have a fever if your temperature is 38°C or higher. > A normal temperature is around 36-37°C, although it depends on your age, what you’ve been doing, the time of day and how you take the measurement. ( further notes on taking temp., children, etc. ) https://www.healthdirect.gov.au/fever https://www.healthdirect.gov.au/fever
- iopq 4y agoYes, it's a conversion of 37C which is stupid since 37C is when I have a fever already
- kyriakos 4y ago37 may or may not be a fever depending on your activity. If you went running your body temperature will be above 37 but you'll feel perfectly normal. When you got 37 and it's a fever it feels different.
- mateo1 4y agoKnowing that my resting body temp was permanently 36.8-36.9 while everyone elses (on the same thermometer) was 36.6 was one of the things that led me realise something was wrong and in fact it turned out I had an autoimmune. Of course the temperature fluctuates with activity and with the time of the day but an auxiliary reading of 36.6 has been what I've always observed for myself and others. After all we all run the same biochemical processes that are optimal at this temp. As a side note, I hate digital contact thermometers with passion. Mercury is dangerous as hell but if it wasn't for gallium alloy ones I'd smuggle them in the country.
- EduardoBautista 4y agoI have always felt that 37C was way too precise an answer for a human's body temperature. How is it that a measurement based on the freezing and boiling point for water coincidentally lands on a nice even number for a human's body temperature. It's one of my issues with biological sciences that they sometimes try to come up with precise answers as they do in physics or chemistry, when most of the time answers, such as this, should be phrased as "around 37C" instead of "it's 37C".
- travisjungroth 4y agoEven “around” is meaningless without context. A hot day is around 37c (+/- 10), a healthy person is around 37c (+/- 1) and a manufacturing process could call for a temp around 37c (+/- 0.1).
- kolinko 4y agoThe accuracy is implied in the nimber of dogots usually. So 37 is +-1C, 40 is +-10, and 36.6 is +-0.1
- travisjungroth 4y agoDoesn’t work great when you want high precision on a number that ends with zeros or have a range that’s not a multiple of ten. The real answer is standard deviation or something like that.
- TylerE 4y agoSure it does. 10000 and 10000.000 have vastly different precision.
- travisjungroth 4y ago10,000 doesn’t disambiguate between an error of 1, 10, 100 or 1000.
- kolinko 4y agoIn Poland normal has always been considered 36.6C, which is 97.9F, which the article states as a proposed new normal.
- romwell 4y agoSame in Russia, Ukraine, and other former USSR countries AFAIK
- throwaway290 4y ago37 degrees (98.6 F) could already get you off school if you're lucky...
- voytec 4y agoTo add, < 38°C (100.4°F) is not considered a fever but subfebrile.
- albertopv 4y agoSometimes I feel more sick having 37.5° than 38°, I don't know why.
- Barrin92 4y ago"In Wunderlich’s day, tuberculosis, syphilis, chronic gum disease, and other inflammatory conditions that can raise body temperature were common" That part resonates with me. I had a pretty bad tooth infection after delaying seeing a dentist for a cavity. (which is a mistake I will not make again), and during the few months I had a body temp probably a degree celsius higher than usual. Given the state of dental health over 150 years ago and that a lot of data came from soldiers there may just have been a lot of inflammation going on.
- ghshephard 4y agoAs someone who has always been 96.5/35.8 - I will say that having a higher body temperature being the standard works out well when you come running in flushed to your check-in gate at the airport, and they take your body temperature (Covid thing) - and you still come in well under the acceptable range.
- ls15 4y agoDuring the pandemic, some shopping centers in my area started to measure wrist temperatures. Once, my wrist was still cold from winter temperatures outside: "28.5, ok, next"
- cesarb 4y ago> During the pandemic, some shopping centers in my area started to measure wrist temperatures. They were supposed to measure your forehead temperature with that infrared thermometer. But due to some insane rumor spread around the net about these thermometers somehow hurting the pineal gland or something like that, everyone starting measuring on the wrist, even though it's way less accurate.
- eyelidlessness 4y agoOh cool, I don’t just run cool, everyone does. Cool cool cool.
- aaron695 4y ago[dead]
- Mistletoe 4y agoI was glad to read this, I’ve thought every thermometer I’ve ever had was inaccurate when I get readings like 97.5 all the time…
- pauljurczak 4y agoSame here. Usually around 96.6F oral.
- paulpauper 4y agoNormal body temperature seems to be falling over time. An analysis of 20 studies between 1935 and 1999 found that the average oral temperature was 97.5˚ F. And a 2017 study of more than 35,000 people found an average body temperature of 97.9˚ F. I wonder if this can explain rising worldwide rates of obesity.
- xeromal 4y agoIt's mentioned in the article that being overwhere is a potential explanation. Hard work surely increases your body temperature.
- zoklet-enjoyer 4y agoI heard about this on a podcast but don't remember which podcast it was on. More fungal infections possibly because body temperatures are decreasing. https://www.wired.com/story/fungi-climate-change-medicine-health/ https://www.wired.com/story/fungi-climate-change-medicine-he...
- rvbissell 4y agoRadiolab. One of their best episodes, IMO. https://radiolab.org/episodes/fungus-amungus https://radiolab.org/episodes/fungus-amungus
- BeetleB 4y agoSeveral people in the medical field have told me they do not consider 99.x as a fever. Edit: Found a link: https://www.osfhealthcare.org/blog/whats-considered-a-fever-and-when-to-see-a-doctor/ https://www.osfhealthcare.org/blog/whats-considered-a-fever-... 100.4 is their threshold.
- poulsbohemian 4y agoAs a dad, I don't consider my kids to have a fever until they are closing in on 101. They each run hot to begin with, but also the thermometers generally available to the public never seem to be particularly accurate.
- nano9 4y ago> [One key possibility] ... Lower metabolic rate: One of the biggest determinants of body temperature is your metabolic rate. Like a car engine that’s idling, your body expends energy just keeping things going, and that generates heat. A lower metabolic rate in modern times could be due to higher body mass (some studies link this with lower metabolic rate), or better medical treatments, preventive measures, and overall health. I know it's not exactly "thinking with statistics", but it strikes me as too coincidental that the obesity epidemic has only exploded in recent decades too.
- BoiledCabbage 4y agoIt seems very likely to be metabolic rate. Most people are way more sedentary than in the past. I'm curious how direct it is. If someone starts exercising from being sedentary for years does their body temperature raise appreciably?
- bee_rider 4y agoI wouldn’t be that surprised to hear that they were always running slight fevers, though. The past was disgusting.
- paulpauper 4y agoIt makes sense. I think it explains some of it.
- silisili 4y agoThis is what I came to say. When I was a teen my body ran hot, so hot people used to even comment at times it felt like I had heat coming off me. My normal temps were in the low 99. Now, as an adult, my metabolism nosedived. I barely feel like eating once a day. It's not abnormal to get temps in the 96s, though that could just be the cheap covid thermometers.
- beagle3 4y agoI'm in my late 40s, people around me still comment that I'm radiating heat (and have commented that for at least 30 years), and I almost always feel too hot - used to walk with a short sleeve shirt in the dead of snowy winter when I lived in NYC. But my temperature when measured is consistently below 36 celsius, often 35.
- bhaney 4y agoIs it possible that thermometer calibration has just drifted slightly over the last couple hundred years? If you told me that the typical electronic thermometer today actually measured around a degree different than the mercury thermometer Wunderlich presumably used, I wouldn't be all too surprised. Or is there really an accurate and consistent calibration technique that's been in use since at least the 1800s, so we know for sure that it must be humans themselves getting cooler?
- sublinear 4y agoUh surely "mmHg" is a stable unit of measurement where the calibration is self-evident by its own definition.
- hamandcheese 4y agommHg is a unit of pressure, not temperature. Mercury thermometers do need to be calibrated.
- kbelder 4y agofreezing point of water/boiling point of water are pretty stable temperature checkpoints, once we learned to fix pressure and contamination....
- deleted 4y ago[deleted]
- g_log 4y agoAnother hypothesis that I've come across on some alternative health sites is that the increased consumption of polyunsaturated fats is responsible for a decrease in metabolic rate/body temperature. https://fireinabottle.net/this-is-your-body-temperature-on-vegetable-oil/ https://fireinabottle.net/this-is-your-body-temperature-on-v...
- kqr 4y agoThe whole enterprise of trying to find "a normal" temperature seems silly to me, increasingly after getting two kids with fevers every now and then. We use both high-quality ear canal and anal thermometers, and while we have enough statistical grounds to unbias their results compared to each other, there remains significant variance. I.e. if we use an anal or ear canal thermometer makes temperature vary ±0.4 °C. Then how sloppily you take the measurement with the same thermometer can result in a ±0.2 °C difference for the butt, and ±0.6 °C for the ear canal. Of course, the time of day we take the temperature can give us a ±0.5 °C difference, and the activity level of the person something like a ±1 °C difference (we don't have as much data on these last ones, naturally.) And all this is before you bring in the fever! So all of this we consider normal. Basically, in our experience, anything below 38.4 °C could just as well be caused by any of a number of non-fever conditions at something like a 90 % confidence level, so unless there's a strong prior of fever, a "non-normal" temperature reading on its own is a fairly weak signal. ...which brings me to my final point: the prior ought to strongly affect what counts as normal temperature, but all of this discussion ignores it. There's also the question whether you prefer false positives or false negatives when it comes to fever detection. My impression is that the medical community prefers false negatives, i.e. pretending that people with a low fever are perfectly normal -- but a lot of private persons I talk to have the opposite preference: they would prefer to think of someone as sick even though they are healthy. Like any good medical test, you pick a threshold based on what probability you want for false positives and negatives, and you weigh the prior into this judgment. Just investigating what an average resting temperature with a particular measurement method seems to me silly.
- saurik 4y ago> if we use an anal or ear canal thermometer makes temperature vary ±0.4 °C. This part is just known, though: the usual "close enough" standard for core temperature is an anal temperature and everything else you have to adjust. (Everything else you say I agree with, though.)
- kqr 4y agoI know that's common wisdom, but I also have started to doubt it -- when variation is so large, does it really matter whether you measure in the ear or the butt? (For what it's worth, my local hospitals use ear canal temperatures for diagnostic purposes.)
- WA 4y agoWomen with natural menstrual cycles have a 0.2-0.5 °C higher body temperature after their ovulation because of the higher progesterone level in their blood. They literally don’t have a single "correct" body temperature. It’s not mentioned in the article, which I find odd, because it tells you something about averaging statistics and male body bias in science.
- Moru 4y agoA lot of it is chosen male because female body is more complicated in some ways. We are just figuring things out with statistics and some things will be wrong if we cut out 50% of the population. Sience is starting to wake up to this though, but slowly.
- eterevsky 4y agoWhen I grew up I've always been told that the "normal" temperature is 36.6 C, which is much closer to the value from this article than 37 C.
- qwerty456127 4y agoPerhaps the temperature of the perfectly healthy state can vary between people as can their sensitivity to deviations. As for me, though, it has always been exactly 36.6°C. The idea of somebody telling me 37°C is healthy drives me mad because I feel terrible at 37°C, such temperature indicates I am surely sick and will probably infect others. As soon as my temperature deviates from 36.6°C (36.65°C is Ok, 36.7°C is not) I immediately feel physical discomfort in my whole body and that is not a placebo effect - I feel it first and confirm it with a measurement after. I measure my temperature in my armpit using a classic mercury thermometer. I tried an electronic thermometer but found it imprecise. This way I want to defend 36.6°C as the normal temperature and to abolish 37°C being considered normal as well. Perhaps it can be normal but that would be an individual trait of a specific person. Unless such a temperature is proven normal for this specific person, a person with 37°C armpit temperature should not be allowed to visit the office, attend flights etc.
- incrudible 4y agoUncharitable reading: People are getting fatter and more sedentiary, lowering the normal body temperature. More than ever, we need a distinction between normal and healthy.
- petodo 4y agoPeople worry too much about temperature/fever, if you have efever (clearly) caused by infection anything below 40.6C is fine and safe and fever reducing drugs are just to make you more comfortable, but they don't really lower any danger. It's common myth people thinking their kids brain can get fried from infection, which is pretty much impossible, it can get fried from overheating in hot enviroment, but it's pretty much impossible just from infection. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145646/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4145646/
- mackman 4y agoIn the afternoon my son’s temperature is closer to 99.5. Of course I never measured it unless I thought he was sick and confirmation bias led me to believe he was feverish. I finally started checking it in the afternoon when he seemed well and realized he was just always warm in the afternoon and all that worrying about his “fever” was pointless.
- lukeschlather 4y agoI want to see a study where they bring in people, measure their temperature, then have them walk a mile then measure their temperature again. The decrease seems small enough that it could completely be an artifact of point-in-time activity levels. Everyone drives to the appointment now where two centuries ago they would've probably walked.
- lamontcg 4y agoYeah, I tend to run at 97.5 normally and 98.6 usually comes with some aches and pains and a slight feverish feeling that I suspect is an abortive infection (tend to get those 1-3 times a year in the fall/winter, although I didn't at all throughout the 20/21 fall/winter). "I have a normal temperature so I kinda feel half like ass and think I'm going to stay home today"
- ngcc_hk 4y agoThe need to have one number is strong, even though as said it is function of a lot of factors and even change over time. It is not the “normal” or average (median, mean, ..) but what is having a temperature that is more important. 100f … is that a good indicator is the issue for a vital sign like blood pressures, heart rate and breathing rate etc.
- netmonk 4y agoTime to understand that modern standard diet is inducing hibernating mechanism in human and therefore is lowering body temp by around 1 degree celsius as one of the least worse side effect (obesity, diabete, hypertension...)