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I heard from a Japanese person that Japanese people have a lower body temperature than caucasians. Is this the case?

Examples from the internet of people discussing claims that Japanese people, or asians in general, have a lower body temperature

Straight Dope thread:

My Japanese girlfriend tells me that Asians have a lower body temperature than honkies.

...

I dont have a link, but it is common knowledge in Japan, that we Japanese have a slightly lower body temperature than other ethnic groups. Instead of 98.6, ours is about 98.

Big Daikon thread

Japanese people have lower body temperatures

A lady ... set forth this assertion ... and was upset I refused to believe it.

... [on the next page] There was a Discovery Channel special on surviving in cold places and how some people adapt. They put a caucasian army officer and an inuit hunter the same age into a -20 meat locker wearing only shorts and a T-shirt. They had them wired up to check their vitals. The Inuit's body temp. dropped, but in small, steady amounts over a 30min period. The army dude on the other hand was near-hypothermic by the end.

I have no doubt that certain people's heritages, based on environment can have certain advantages/disadvantages over the other. That's only natural. But for someone to suggest that Japanese, rather than mongoloid are X or Y is cultural jingoism bubbling to the surface (not limited to Japan, of course).

As far as I can tell, the putative explanation is that some (but not all) people in Japan are ethnically different from some (but not all) people living in countries in Europe, North America, or Australia, and that those ethnic differences may be associated with different average body temperature.

While I'm primarily interested in Japanese people, any answer with a reliable source that says different ethnic groups have different body temperatures will be welcome. If you're of the opinion that different ethnic groups do not exist, then this claim may be a little hard to negate, but a study showing no differences between body temperature of people who live in Japan and people who live in a country perceived as predominantly caucasian would go a long way to debunking this myth.

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  • Related: biology.stackexchange.com/questions/54127/… and health.stackexchange.com/questions/9981/…
    – Always Confused
    Dec 13, 2016 at 18:42
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    Leaving my personal anecdotal evidence as a side-note (too insignificant to warrant a separate answer): Every Japanese I've talked to about it were surprised to hear that my baseline body temperature is over 37'C. One of my coworkers (aged around 60), claimed a body temperature of about 35.5'C. I never cared to do a bigger survey on this, it's just something that seemed quite obviously to be true, and I never came across any opinions or data to the contrary.
    – Eirik Birkeland
    Oct 14, 2017 at 15:13
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    For what it's worth, in France the normal average temperature is considered to be 37°, while in Russia 36.6 is consider to be the normal average, and in Hungary it's 36.5. (The source personal evidence of what people grow up thinking to be normal in those countries.)
    – Fabien Snauwaert
    Jun 18, 2018 at 20:54
  • Japan is a big country spanning different climate zones. I would expect to see different adaptations among different groups of Japanese people depending on the area where they live. Already a claim putting together all the Japanese people sounds far fetched.
    – FluidCode
    Sep 18, 2022 at 14:47

1 Answer 1

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There may be a difference, depending on whether you are talking about internal or skin temperatures.

This study compared 9 Japanese men to the results of a similar study done in Ohio with Caucasian men:

The subjects were made to walk on a treadmill for 2 hours, in carefully controlled conditions.

There were a number of differences in the amount and composition of their sweat.

Internally, they maintained the same body temperature:

There were no differences in rectal temperature or heart rate, both at the period of equilibrium rectal temperature and at the end of the walk.

However, there were differences in the skin temperature - perhaps not in the direction you were expecting:

Mean skin temperature during the walk was significantly higher in Japanese than in Caucasians.

They concluded that:

the Japanese group was better heat acclimatized than Caucasians, though the two groups were considered to have been naturally heat exposed by season to the same extent.

While this result is suggestive, I don't find it to be definitive, as the caucasians were tested at a different time in a different facility, making them a poor control. Also the sample sizes were small, in an area which may vary by age and other factors.

This study didn't involve Caucasians, but compared Malaysians ("tropical natives") and Japanese males.

They put them under a number of different scenarios, such as soaking their feet in a warm bath, but also at resting.

The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest [...]

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    The first study has to be misleading, and yes, has extremely inconclusive sample sizes. Westerners in Japan are over-diagnosed fever in Japan and Japanese people raise alarm with their low body temperature in the west. I found this, which might have info, but is paywalled: health.harvard.edu/press_releases/normal_body_temperature
    – flying sheep
    Apr 7, 2020 at 13:47
  • @flyingsheep: Is there a word missing in your comment? Over what? Also, I do not know what you mean when you saw the effect is stable across borders, or why you believe the measuring equipment (or other experimental set-up) would not be responsible for the difference.
    – Oddthinking ♦
    Apr 7, 2020 at 13:50
  • Same rectal temperature --> same "body temperature" --> answer to the question is "no".
    – Colin
    Apr 8, 2020 at 7:54
  • That's why I said the study is misleading in relation to the commonly observed phenomenon of lower measurements from Japanese people. If I had to speculate, I'd say that maybe the extremity temperatures are on average lower in Japanese people compared to Westerners while the core temperature is the same.
    – flying sheep
    Apr 8, 2020 at 9:53
  • @flyingsheep: I suspect you are begging the question. If this is a commonly observed phenomena, please link to this empirical evidence in an answer. I don't think it is a commonly observed phenomena.
    – Oddthinking ♦
    Apr 8, 2020 at 16:43

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