# Are African-Americans More Likely to Get Frostbite? **URL:** \ **Category:** Factual Questions\ **Created:** [November 26, 2004, 2:23am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697 "2004-11-26T02:23:56Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [November 27, 2004, 11:03pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/21 "2004-11-27T23:03:04Z")
**Askia** , **Shalmanese** is referring to is the hypothermic vasosconstrictive response, which, when the temperature drops below a certain point, causes the veins in the extremities to close off, keeping the body core warm. I’m well-acquainted with this phenomenon because I have Raynaud’s disease, so I experience this response pretty much every time the temperature is a few degrees below room-temperature. (Think freaky white bloodless hands every time I reach into the fridge. Ugh.) Hurts like a sonofabitch when I come in from the cold, too. Your tissue freezes a lot faster when warm blood stops reaching it. A bit of googling turns up that **Shalmanese** is correct about this response being mitigated in Inuit peoples, as well as people of European ancestry, and also that African-American folks may be at a higher risk of frostbite because they lack it, at least according to [this cite](http://www.wku.edu/~darlene.applegate/humanvariation/lab4.html): > [@](#): > > Genetic responses to cold stress that address the problem of heat conservation include […] cold-induced vasodilation (CIVD). CIVD is cyclical rewarming of the extremities through vasodilation. There is an alternation between vasoconstriction, which warms the body trunk, and vasodilation, which warms the extremities. CIVD functions to reduce the dangers of frostbite of the extremities. It is common in Arctic dwellers such as the Inuit (“Eskimos”), other Native Americans, and European-Americans, but it is not found among African and African-American populations. I am a _little bit_ doubtful about that unqualified “not found among … African-American populations,” though. Surely most African-Americans share a common genetic heritage with European-Americans. I’m no geneticist, of course. Could this trait be so recessive that it’s _never_ passed on if one of the genetic donors has “one drop” of “African blood” in their family tree? ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 27, 2004, 11:12pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/22 "2004-11-27T23:12:03Z")
“I’ve never seen frostbite on a black guy before. It looks kinda… blue.” -Tom Berenger to Sidney Poitier in _Shoot to Kill_ ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [November 27, 2004, 11:21pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/23 "2004-11-27T23:21:21Z")
I have heard of hypothermic vasosconstrictive response in terms of male and female where a study by the military (sorry no cite, many years ago) found that men they tested generally have this, while women generally don’t. It went on to propose that the use of extremities were a benefit to men who must use tools to hunt and survive, while it was more important for females to protect core temps as to protect her unborn child. ---
**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\ **Post date:** [November 28, 2004, 12:13am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/24 "2004-11-28T00:13:38Z")
I worked with an Innuit guy for a while in summertime in Bakersfield building a salf-contained drilling rig for use in Alaska. He was a rep for the drilling company. Anyway, he had a very hard time with the heat (everyday was 95+, usually 100+), and he sometimes showed early signs of heat stroke. Eventually had to return home. He was ok at temps up to 85 or so. Peace, mangeorge ---
**Author:** ![The\_Llama](https://avatars.discourse-cdn.com/v4/letter/t/a698b9/32.png) [@The\_Llama](https://boards.straightdope.com/u/The_Llama)\ **Post date:** [November 28, 2004, 1:01am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/25 "2004-11-28T01:01:40Z")
I would just like to add, from a logic standpoint, that just because people may have 1 or 2 characteristics that help them survive better in the heat, doesn’t mean that they’re going to specifically lack the things that help them survive in the cold. Darker skin has more melanin. This helps you survive better in the sun in that it protects you from UV and solar radiation. As far as I know, though, melanin doesn’t sap your heat from you. So I think it’s kind of ridiculous to base your assumption that black people might suffer frostbite more easily simply because of some superficial qualities. I think it’s even more ridiculous to use Eskimos as your correlation as to why it may be so. The Eskimo example is different because it’s an issue where they may be able to get more blood to an extremity in times of cold… of course this will make heat harder for them, because there’s no way to shut the blood flow off. In fact, they’d probably get more blood to the extremities with the veins being less constricted in the heat and, therefore, would get hotter, faster. So here, you can’t say that because people adapted in cold environs have a hard time in the heat, people adapted for heat environs will have a hard time in the cold. Especially when the adaptations came about in drastically different physiological manners. It is simply not a logical correlation. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [November 28, 2004, 1:29am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/26 "2004-11-28T01:29:03Z")
**Most likely in MN and least likely in FL!** ---
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [November 28, 2004, 1:53am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/27 "2004-11-28T01:53:04Z")
> [@The\_Llama](#): > > The Eskimo example is different because it’s an issue where they may be able to get more blood to an extremity in times of cold… of course this will make heat harder for them, because there’s no way to shut the blood flow off. You misunderstand. The vasodilation is an adapted _response to cold_, shared by people with ethnic roots in places with cold climates, ie, Europe and North America. It has nothing to do with having a harder time dealing with heat. The alternating constriction/dilation of blood vessels in the extremities does not take place _unless it’s very cold._ If an Inuit (or Native American/European-descended) person has a hard time dealing with heat, it’s because of other physical factors such as the shape of the body, extremities, or nose, the amount of body fat, or even (and perhaps especially) simple individual acclimatization. > [@The\_Llama](#): > > So here, you can’t say that because people adapted in cold environs have a hard time in the heat, people adapted for heat environs will have a hard time in the cold. Especially when the adaptations came about in drastically different physiological manners. It is simply not a logical correlation. You’re right, there’s no logical connection between those two premises – however, this is an unecessarily complex form you’ve given it. Try this: Ethnic groups who have adapted in cold environs do better in cold environs than those who have not. If someone with genetic roots in Europe or North America is exposed to extreme cold, the response is a slow oscillation of blood supply to the extremities. Stop it to keep the body core warm – then restart it to forestall frostbite, and repeat as necessary. For folks with African ancestry (well, more immediate African ancestry than the rest of us, anyway,) the response to extreme cold is just to cut off blood to the extremities, until it either warms up or fingers and toes fall off, because they don’t have the benefit of the vasodilation response. ---
**Author:** ![The\_Llama](https://avatars.discourse-cdn.com/v4/letter/t/a698b9/32.png) [@The\_Llama](https://boards.straightdope.com/u/The_Llama)\ **Post date:** [November 28, 2004, 4:49am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/28 "2004-11-28T04:49:10Z")
> [@Larry Mudd](#): > > You misunderstand. The vasodilation is an adapted _response to cold_, shared by people with ethnic roots in places with cold climates, ie, Europe and North America. It has nothing to do with having a harder time dealing with heat. The alternating constriction/dilation of blood vessels in the extremities does not take place _unless it’s very cold._ If an Inuit (or Native American/European-descended) person has a hard time dealing with heat, it’s because of other physical factors such as the shape of the body, extremities, or nose, the amount of body fat, or even (and perhaps especially) simple individual acclimatization. You’re right, I obviously misunderstood. And I think I sounded kind of snide in my explanation… serves me right. Just so I’m clear, then, vasodilatation is when the temperature drops to -10F (just a random number for example) and Mr. Eskimo’s veins say “hey, it’s freaking cold, we need to get more blood to the toes!” and they dilate. But otherwise, at normal temps, or even hot temps, the veins say nothin… they just chug along like normal? ---
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [November 28, 2004, 6:58am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/29 "2004-11-28T06:58:14Z")
It’s not just Mr. Eskimo, apparently-- it is supposedly common to everyone except folks of African descent, (oh, and women, as **kanicbird** recalled.) _Everyone_ has the vasoconstriction response to cold, which keeps the body core warm. Everyone _except,_ (it is asserted,) African-descended folks (oh, and women) has the vasodilation response, which cyclically allows blood to flow to the extremities until they warm up again, helping to prevent frostbite. Then the vasoconstriction kicks in again, and the cycle repeats, hopefully until the person has the sense to come in from the cold. Here’s a [more detailed explanation](http://herkules.oulu.fi/isbn9514259882/html/c287.html) of cold-induced vasodilation/vasoconstriction. (I have edited out numerous cites in the quoted text for readability.) > [@](#): > > A specific rhythmical cold-induced vasodilation […] of the vasculature protects especially the peripheral extremities from rapid and permanent damage by enhancing the total blood flow. After the skin temperature in hands and feet underlies +10_C the [arteriovenous anastomoses] lose their vasoconstriction from time to time and increase the circulating blood in fingers and toes warming them up temporarily by even 5—10_C, which is then followed by a new vasoconstriction and cooling wave when the vessel walls have regained their reactivity to regulatory mechanisms. Waves follow each other in rhythm that varies individually. CIVD is strong in normothermic subjects but weak, retarded or absent in hypothermia and hyperthermia. In African-Americans and female gender CIVD is much weaker or totally absent, and in people living regularly in Arctic it may be especially strong, although the data of different studies is partially controversial. ---
**Author:** ![mmmiiikkkeee](https://avatars.discourse-cdn.com/v4/letter/m/edb3f5/32.png) [@mmmiiikkkeee](https://boards.straightdope.com/u/mmmiiikkkeee)\ **Post date:** [November 28, 2004, 7:04am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/30 "2004-11-28T07:04:46Z")
Wouldn’t sending blood through the extremities (even alternating) when it’s very cold make a person more likely to freeze to death in the long run as they are loosing all that extra heat? ---
**Author:** ![mmmiiikkkeee](https://avatars.discourse-cdn.com/v4/letter/m/edb3f5/32.png) [@mmmiiikkkeee](https://boards.straightdope.com/u/mmmiiikkkeee)\ **Post date:** [November 28, 2004, 7:09am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/31 "2004-11-28T07:09:29Z")
Oh sure, just before I post up goes an article saying this cycle only happens in regular body temp ranges, and not in the hypothermic conditions I was thinking this system would be harmful in… rrrrgh. ---
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [November 28, 2004, 7:27am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/32 "2004-11-28T07:27:37Z")
Heh. Sorry. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [November 28, 2004, 12:39pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/33 "2004-11-28T12:39:18Z")
> [@](#): > > Wouldn’t sending blood through the extremities (even alternating) when it’s very cold make a person more likely to freeze to death in the long run as they are loosing all that extra heat? It depends, if Nankoo is outside his warm igloo and all he needs to do is put his key in the lock and turn it, he better be able to use his hands to do it. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [November 28, 2004, 1:38pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/34 "2004-11-28T13:38:54Z")
While I think there may be some physiological differences, there are also cultural ones. A good friend of mine is from the Democratic Republic of Congo. It gets hot there. Really hot. The two of us were hanging out in Indiana one July day - it was maybe 102 or so. Hot, but not Congo hot. Both of us are larger women - actually very similarly shaped, with about the same muscle/fat ratio. I was a drippy, wheezing mess. I was utterly miserable. Kabuika was happy as a clam. I suggested we walk to the shaded part of the land, and about four steps into our walk, she stopped me, laughing. “Why are you walking like that? You’ll burn up!” She taught me a completely different pacing and way of holding and moving my body, and I was suddenly comfortable. The temperature was exactly the same, but I was suddenly OK in the bright sunlight. She, born and raised in a much warmer climate than I, had never been “taught” how to move like this - it was just how you walked. I had to be taught. And now I’m pretty much OK even on the hottest midwest days. Perhaps there are similar behavioral differences that people who grow up in cold climates just “know” - like keeping your hands tucked into your body or stamping your feet instead of standing still. Maybe a woman from Africa could use some help learning those tricks. I think \*\*Loach \*\*may be onto something. I’ve seen frostbite on both Anglo and African skin, and it’s much harder to spot early on African skin. That could easily lead to ignoring really cold hands and feet and missing the early stages of frostbite. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [November 28, 2004, 6:57pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/35 "2004-11-28T18:57:41Z")
> [@The\_Llama](#): > > of course this will make heat harder for them, because there’s no way to shut the blood flow off. In fact, they’d probably get more blood to the extremities with the veins being less constricted in the heat and, therefore, would get hotter, faster. And I don’t think this is true, either. I believe that our blood flow to our extremeties increases in high temperatures for the very purposes of allowing us to vent as much heat as possible, so that we do not overheat our cores. The flushed appearance of people in the summer attests to this. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [November 28, 2004, 7:12pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/36 "2004-11-28T19:12:49Z")
I have a book that cites the supposed susceptibility of black people to getting frostbite as a reason for a British employer turning down job applicants in a meat factory. :rolleyes: As for blood thin/thickness, many Tibetans and Nepalese who live at high altitude do indeed have thicker blood than people who live at lower levels. This is evidenced with their very rosy cheeks, though I can’t remember the technical term. I am unsure as to whether this is genetic or just a situational adaptation, though. ---
**Author:** ![Askia](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Askia](https://boards.straightdope.com/u/Askia)\ **Post date:** [November 28, 2004, 7:35pm UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/37 "2004-11-28T19:35:44Z")
**Larry Mudd.** Thank you for clarifying what the hypothermic vasosconstrictive response is. Closed off veins makes a lot more sense than describing it as rerouted blood, and I wouldn’t have been so dismissive of Shalmanese’s assertion had the correct term been used. **WhyNot.** Your experience coping with the heat intrigues me. Care to elaborate on how you used to move and carry yourself in the heat, and what you changed in walking / body movements to cope with the sun better? ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [November 29, 2004, 12:08am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/38 "2004-11-29T00:08:45Z")
> [@Askia](#): > > **WhyNot.** Your experience coping with the heat intrigues me. Care to elaborate on how you used to move and carry yourself in the heat, and what you changed in walking / body movements to cope with the sun better? Well, I don’t really know how I used to move, I just … moved. Sort of city girl pace, I suppose. As for what Kabuika taught me, it’s very hard to explain in words only. (I’m gesturing emphatically to my monitor, just so you know.) In very general terms, it involved slowing down (but not very much, and once I mastered it we could walk as quickly as we liked) but moving more rhythmically. She showed me how to reverse the pendulum swing of my body - making my feet the pendulum instead of my head. Apparently, that’s the trick to carrying those huge baskets on your head, but it also changed the pacing of my walk. Beyond that, I suppose I learned to move more from the core muscles in my trunk, so less energy was wasted (and released as heat) by straining the smaller muscles in my arms and legs. I immediately felt heavier around my pelvic bowl, so I think my center of gravity was lowered, as well. It felt almost the “opposite” of the way I was taught to walk in Bali. There, a native woman had to instruct me on how to walk in those insanely tight sarongs they wear on formal occasions. There, it’s all about keeping your body nearly completely still from the knees up, and walking in little mincing steps from the knees down. Walking down stairs involves crossing your legs at the knee, keeping your thighs together and holding your foot parallel to the step, turned out, instead of perpendicular like I’m used to. It was a very difficult walk for me to learn, but it gives the women an almost unearthly grace. Who woulda thunk that walking could vary so widely between cultures? ---
**Author:** ![I\_Love\_Me\_Vol.I](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/i_love_me_vol.i/32/521_2.png) [@I\_Love\_Me\_Vol.I](https://boards.straightdope.com/u/I_Love_Me_Vol.I)\ **Post date:** [November 29, 2004, 1:04am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/39 "2004-11-29T01:04:51Z")
**Wendall Wagner** said: > [@](#): > > The term “thinner blood” doesn’t even make sense, so that claim is meaningless. Is this really true? Aren’t there medicines (such as aspirin?) that are designed to thin peoples’ blood? If so, doesn’t this suggest that blood’s “thinness” (viscosity?) can vary and therefore that it is possible that blood could be thinner or thicker depending on the individual? ---
**Author:** ![Larry\_Mudd](https://avatars.discourse-cdn.com/v4/letter/l/f14d63/32.png) [@Larry\_Mudd](https://boards.straightdope.com/u/Larry_Mudd)\ **Post date:** [November 29, 2004, 3:36am UTC](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697/40 "2004-11-29T03:36:16Z")
> [@I Love Me](#): > > Aren’t there medicines (such as aspirin?) that are designed to thin peoples’ blood? Aspirin isn’t technically a blood thinner, it reduces a type of protein that is associated with inflammation in certain pathologies. Even actual “blood thinners” like warfarin aren’t blood thinners _per se_ – they’re anticoagulants. They prevent clotting – they don’t make circulating blood thinner. While we’re on the subject, the folk wisdom that chronically cold people are “thin-blooded” is not literally true – more likely it’s a holdover from the time that physicians related everything to the “balancing of the humours,” and people of sanguine temperament were considered to be least-susceptible to the influence of cold. [Previous page](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697.md?page=1) [Next page](https://boards.straightdope.com/t/are-african-americans-more-likely-to-get-frostbite/276697.md?page=3)