5 ms·
> During their simulation of Mallory’s Everest expedition, the data showed that on summit night, the average body temperature difference between the twin in mod
by pinkmuffinere 7mo ago
> During their simulation of Mallory’s Everest expedition, the data showed that on summit night, the average body temperature difference between the twin in modern down and the twin in complicated layers of silk, wool, and gabardine was a staggering 1.8°C.
The human body self-regulates, and is pretty sensitive to dramatic temperature swings. So, conditioned on the fact that they both survived the adventure, we should expect their temperature differences to be relatively small. This doesn't mean the clothing is great, it means [their body] + [their clothing] is adequate.
Additionally, I'm not a doctor but 1.8 C is not small compared to normal human variation! Normal body temperature ranges between 36 and 37 C, a "high fever" starts around 39 C [0], and hypothermia is anything below 35 C [1]. The comfortable range of human temperature is 1 deg C, and the "outside of this is concerning" range is only 4 C wide. 1.8 C is quite big from that perspective.
[0] https://www.health.harvard.edu/diseases-and-conditions/treating-fever-in-adults https://www.health.harvard.edu/diseases-and-conditions/treat...
[1] https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682 https://www.mayoclinic.org/diseases-conditions/hypothermia/s...
- ginko 7mo agoNot to be a stickler (ok I like being a stickler) but temperature delta, especially deltas between degrees celsius, should be given in kelvin. A 1.8K difference makes sense. A 1.8C difference would be 274.8 kelvin!
- hn_throwaway_99 7mo agoThat makes no sense. A difference between a read of 37C and 38.8C is still 1.8C.
- ginko 7mo ago[flagged]
- dekhn 7mo agoI'm not entirely sure what point you are trying to make, but this is absolutely false from a scientific perspective. If you believe otherwise, please provide some citations to your beliefs so we can understand what you are trying to say.
- hexer292 7mo agoSaying something is false and then asking for citations doesn't seem that helpful to me. To support your argument, take the following example: Lets take some water at 273.15 Kelvin and add 1 Kelvin of energy to it. The water is now at 274.15 Kelvin. The difference is of 1 Kelvin. If we had the same amount of water at 0 degrees Celsius and added 1 Celsius of energy, the water would now be at 1 Celcius. Converting these values leave us with 273.15 Kelvin and 274.15 Kelvin respectively. You can repeat this experiment (ignoring latent heat) for any value of Kelvin or Celsius, therefore Kevlin and Celsius are interchangeable in reference to temperature comparasion.
- dekhn 7mo agoI believe any chemistry or physics textbook will state (possibly indirectly) how temperature deltas work. But I think it's sufficient to just say that Kelvin and Celsius have the same scale magnitude and just a constant offset.
- hn_throwaway_99 7mo agoDude, you are just completely making shit up, and it makes no sense. So what if Celsius and Kelvin have different 0 points - they are still valid scales and you can talk about differences between 2 measurements. According to your logic it would be impossible to state that two Fahrenheit measurements differ by some number of degrees F - why, I have no idea.
- hightrix 7mo agoTo be a stickler, communication requires respect for your audience. The vast majority of everyone understands a 1.8 degree C delta. I would argue that very few people anywhere would understand a temperature delta given in kelvin.
- ginko 7mo agoHow is expecting readers to not understand what a kelvin is respecting the audience?
- alistairSH 7mo agoKelvin and Celsius use the same unit magnitudes. It would be a 1.8* difference either way.
- hexer292 7mo agoThis is probably the most ridiculous comment I've read in the history of this website. There is no difference in the amount of energy 1 degree Celsius delta and 1 degree Kelvin delta represents. The only (and I really mean only) difference is how zero energy is defined. It is not possible to have negative energy, and that zero Celsius represents the freezing point of water is an artifact of convenience, not of absolute definition.
- hexer292 7mo agoAlso, the way Kelvin is defined necessitates that both degrees are identical. If 10 degrees Celcius defined the boiling point of water at 1 atmosphere (or whatever the actual definition is) then Kelvin would be smaller by a factor of 10. And this applies to both negative and positive K values.
- deleted 7mo ago[deleted]
- zippyman55 7mo agoRanking, Celsius, Centigrade have the degrees. Kelvin is a base unit, absolute and no degree!
- atombender 7mo agoCelsius is not an absolute scale, but that isn't a problem for deltas: (10C - 5C)=5C, (10K-5K)=5K. Celsius is only problematic when multiplying or dividing. 10C is not twice as hot as 5C.
- deleted 7mo ago[deleted]
- altairprime 7mo ago"A 1.8C difference" expands as "A difference of 1.8C" expands as, and here's the ambiguity, either: "An absolute difference of 1.8C, or 274.8K, measured between A and B" or "A relative difference of 1.8C, or 1.8K, is added/subtracted to A/B in order to reach B/A" I don't think the context-free variant with K will improve understanding and decrease confusability in this discussion context, but I appreciate the pointer about it in general. I'll take a lot more care around it in a future thread about space apparel!
- Tyrannosaur 7mo agoNo it doesn't. The absolute difference[1] of 1.8°C is the same as 1.8K; they have the same scale. The subtraction of values cancels out the offset. A relative difference[2], usually given in percent change, has problems with a unit that has an offset zero like Celcius, but that isn't what anybody is using here. It's more than simple subtraction; you have to divide by the reference value. [1] https://en.wikipedia.org/wiki/Absolute_difference#Applications https://en.wikipedia.org/wiki/Absolute_difference#Applicatio... [2] https://en.wikipedia.org/wiki/Relative_difference https://en.wikipedia.org/wiki/Relative_difference
- Terr_ 7mo ago> A 1.8K difference makes sense. A 1.8C difference would be 274.8 kelvin! I think there was some insight here that went off on a bad tangent leading to a math word-problem mistake, confusing these two: 1. A difference... between [X] and [Y], which is a delta of 1.8°C 2. A difference... between [0°K] and a reading of [1.8°C], which is a delta 274.95°K.
- stackghost 7mo ago>A 1.8C difference would be 274.8 kelvin! Categorically and factually incorrect. A 1.8 degree C different would be 1.8 kelvin. The two degrees have different zero points but one degree Celsius and one degree Kelvin are identical in magnitude.
- _Microft 7mo agoTaking differences between degrees Celsius values is absolutely fine. Ratios are undefined because the Celsius scale has no absolute zero while the Kelvin scale has. See: https://en.wikipedia.org/wiki/Level_of_measurement https://en.wikipedia.org/wiki/Level_of_measurement
- bregma 7mo agoYou're just confused by terminology. While 1 C is 273 K, 1 degree Celsius is 1 degree Kelvin. See, a degree is not an absolute unit of measure like a Celsius or a Kelvin, it's a relative difference between two absolute units of measure. When discussing the difference between two separate temperature readings measured in Celsius, degrees Celsius is entirely appropriate. Think of it like time: there is a difference between meeting at 2:00 and meeting two hours from now.
- hn_throwaway_99 7mo agoI didn't see more details in the article, but my guess is they were taking and averaging multiple temperature reads across the body. That is, core temp should only be within a narrow range like you say, but fingertip temp will vary much more widely. All in all I found this to be a very strange article. If you just look at the data, I think a reasonable conclusion is that modern gear is vastly better at its function than old time Mallory gear. It's much lighter and keeps the wearer much warmer than old gear. But the whole tone of the article is about "myth busting" and how there haven't been really that many improvements in gear. I'm just looking at their charts and data and wondering what they're smoking.
- fwipsy 7mo agoI think they're "debunking" a strawman argument that old gear was completely useless
- db48x 7mo agoObviously that older gear wasn’t useless, since real people used it to climb the exact same mountains that people climb today. It’s pretty clear from the text that they have debunked the idea that modern synthetic materials have outstripped older materials in performance. At the start of their project they expected modern gear of similar capabilities to be lighter. What they found was that modern gear’s advantage is primarily that it is simpler to use. Instead of seven carefully–chosen layers of wool and silk, you can wear a single coat. That single coat is also effective over a much larger temperature range than the older clothes. Really this should not be all that surprising, as the expertise required to pick those layers has been condensed by engineers into the design of the coat. The modern climber no longer needs that same expertise, just money to buy the coat. This is the same story of specialization that has powered our economic growth for centuries. You and I no longer need to know how to grow vegetables, or shoe a horse, or design a circuit. There might still be advantages to knowing how to write a sonnet or plan a battle, but for the most part we can leave these tasks to specialists who can get better results than we can. Those specialists in turn can leave other tasks to us. Everyone gets more efficient as a result.
- tantalor 7mo ago"Normal body temperature", ok but these are two mountaineering nerds (not normal) so who knows.
- IAmBroom 7mo agoDo you imagine that "nerds" have different bodies than "normal" people? I mean, sure, they're athletic, but they still go to human doctors, not some sort of xenobiologist veterinarians.
- mauvehaus 7mo agoThey may have started out the same as you or me, but the conditioning and acclimatization they’ve done over their lives certainly makes them more adapted to the activities they’re doing than the average person.
- IAmBroom 7mo agoSerious question: do you really think mountaineers have a different resting core temp than "normal" human beings, as you apparently have claimed?
- ak217 7mo agoRight, the 1.8C difference is substantial in terms of human physiology and indicates a diminished level of comfort as the body fights to keep the temperature up. I also found it funny how they mentioned that modern clothing keeps you warmer longer once you stop moving, then tried to minimize the significance of that. There's a reason "cotton kills" is a cliche. Modern fabrics, windbreaker shells, and engineered layers don't make a huge difference in warm, dry, active conditions - it's when things go sideways that they can be the difference between comfort and fatal hypothermia.
- sandworm101 7mo agoThere are times when layering is not the way to go. One of them is heavy activity in extreme cold. Layers can cause moisture to freeze in bad places. Having lived in a place that often got down to -40, I was always most comfortable with a light synthetic shirt under a single winter coat. No complex layers. And waterproofing isn't needed as there isn't any water around.
- ErroneousBosh 7mo agoI know someone who has three or four different thicknesses of pure lambswool jerseys for wearing while he's cycling, at different air temperatures. It never really gets all that cold down south here at 56°N and frankly I think spending ten minutes dicking about over which jumper you're wearing for optimal performance takes a lot of the fun out of it. That said, I'm a fat 52-year-old, and I cycle in jeans and a T-shirt, and if I start to feel cold it's a sign I'm not pedalling hard enough and I should get the boot down a bit, burn some calories. I'm still faster than many-jerseys-guy.
- carlob 7mo agoI'm curious: I do cycle in jeans and a t-shirt while in the city. Up to 45 minutes I'm perfectly fine, but if I'm on the saddle for over one hour I really start to miss the chamois. What's your experience with that?
- 7mo ago
- WillPostForFood 7mo agoIt was 1.8 C difference in skin temperature, not core body temperature. As you note, 1.8 C would be massive for core temp. Wearable thermometer patches attached to each man’s head, chest, hands, feet, and legs recorded body temperature at five-minute intervals, nonstop, for the entire 10 days of the expedition.
- IAmBroom 7mo agoI'll argue that, if it got down to the sharp edge of survival's knife, only the 2-degree warmer twin would come home. 2 degrees C (3 F) is palpably warmer. That being said, if a 2-degree dip in temp would kill you, you are already praying for Ernest Shackleton's leadership.
- fmajid 7mo agoI'd rather pray for Roald Amundsen's leadership if I wanted to actually survive.
- thinkingemote 7mo agoAny theories or conclusions in the article especially with regards to science and medicine is best ignored as the article was written by an LLM. The photographs and text within quotes are probably the only human things in there. We might go to the source of the data (the brothers instagram) for better conclusions, but for me this well is poisoned by slop.
- eleveriven 7mo agoI think both points can be true at once