4 ms·

You can survive in extreme heat with low humidity. Once the 'wet bulb' temperature exceeds 35 degrees C, sweating is no longer effective, core temperature rises

You can survive in extreme heat with low humidity. Once the 'wet bulb' temperature exceeds 35 degrees C, sweating is no longer effective, core temperature rises, and you die. Extremes of cold must be a different story, about how much insulation can protect core temperature. There's probably a minimum temp at which something like respiration just ceases to work. This article has some good info: https://www.coolantarctica.com/Antarctica%20fact%20file/science/cold_humans.php https://www.coolantarctica.com/Antarctica%20fact%20file/scie...

yesenadam 8y ago
35˚C extreme? You die? That doesn't sound right. Anecdata: There was a strange heat wave here in Sydney about 7 or 8 years ago, where for a week or two it was 35˚ (and humid) all night, every night. It was uncomfortable, sure, but not extreme heat, I wouldn't say. I've never lived in a house with air-conditioning in Australia (and I grew up somewhere hotter than Sydney, which isn't particularly hot), hardly ever used a fan, even.
- deleted 8y ago
  [deleted]
- FooHentai 8y ago
  Doesn't it? The key point though is that this is wet bulb temperatures. Today, there aren't many areas of the globe where that is experienced. "A sustained wet-bulb temperature exceeding 35 °C (95 °F) is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature our bodies switch from shedding heat to the environment, to gaining heat from it." https://en.wikipedia.org/wiki/Wet-bulb_temperature#Wet-bulb_temperature_and_health https://en.wikipedia.org/wiki/Wet-bulb_temperature#Wet-bulb_... "Peak heat stress, quantified by the wet-bulb temperature TW, is surprisingly similar across diverse climates today. TW never exceeds 31 °C. Any exceedence of 35 °C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 °C, calling the habitability of some regions into question. With 11–12 °C warming, such regions would spread to encompass the majority of the human population as currently distributed." https://www.pnas.org/content/107/21/9552.full https://www.pnas.org/content/107/21/9552.full
  - yesenadam 8y ago
    Hmm yeah thanks, hadn't heard of that. e.g. "An example of the threshold at which the human body is no longer able to cool itself and begins to overheat is a humidity level of 50% and a high heat of 46 °C (115 °F), as this would indicate a wet-bulb temperature of 35 °C (95 °F)." (wikip)
- MRD85 8y ago
  I live in Sydney but 4 years ago I lived in the tropics. Sydney doesn't get close to tropical levels of humidity. It's a completely different type of heat. 30 degrees with 100% humidity is fairly unbearable for working outdoors. 42 degrees in Sydney is hot but fluids keep you going. In Townsville, I would experience heat distress doing exercise at 8am due to the humidity. In Sydney, I could do a 5km run in 40 degrees if I wet myself beforehand.

yesenadam 8y ago

35˚C extreme? You die? That doesn't sound right. Anecdata: There was a strange heat wave here in Sydney about 7 or 8 years ago, where for a week or two it was 35˚ (and humid) all night, every night. It was uncomfortable, sure, but not extreme heat, I wouldn't say. I've never lived in a house with air-conditioning in Australia (and I grew up somewhere hotter than Sydney, which isn't particularly hot), hardly ever used a fan, even.

deleted 8y ago
[deleted]
FooHentai 8y ago
Doesn't it? The key point though is that this is wet bulb temperatures. Today, there aren't many areas of the globe where that is experienced. "A sustained wet-bulb temperature exceeding 35 °C (95 °F) is likely to be fatal even to fit and healthy people, unclothed in the shade next to a fan; at this temperature our bodies switch from shedding heat to the environment, to gaining heat from it." https://en.wikipedia.org/wiki/Wet-bulb_temperature#Wet-bulb_temperature_and_health https://en.wikipedia.org/wiki/Wet-bulb_temperature#Wet-bulb_... "Peak heat stress, quantified by the wet-bulb temperature TW, is surprisingly similar across diverse climates today. TW never exceeds 31 °C. Any exceedence of 35 °C for extended periods should induce hyperthermia in humans and other mammals, as dissipation of metabolic heat becomes impossible. While this never happens now, it would begin to occur with global-mean warming of about 7 °C, calling the habitability of some regions into question. With 11–12 °C warming, such regions would spread to encompass the majority of the human population as currently distributed." https://www.pnas.org/content/107/21/9552.full https://www.pnas.org/content/107/21/9552.full
- yesenadam 8y ago
  Hmm yeah thanks, hadn't heard of that. e.g. "An example of the threshold at which the human body is no longer able to cool itself and begins to overheat is a humidity level of 50% and a high heat of 46 °C (115 °F), as this would indicate a wet-bulb temperature of 35 °C (95 °F)." (wikip)
MRD85 8y ago
I live in Sydney but 4 years ago I lived in the tropics. Sydney doesn't get close to tropical levels of humidity. It's a completely different type of heat. 30 degrees with 100% humidity is fairly unbearable for working outdoors. 42 degrees in Sydney is hot but fluids keep you going. In Townsville, I would experience heat distress doing exercise at 8am due to the humidity. In Sydney, I could do a 5km run in 40 degrees if I wet myself beforehand.