Question: How long can a person survive before effects of heat stroke start to affect them.

Situation. A person is in a room that is heated up to 75 C (167 F). Let's assume person is naked (so we don't have to factor in clothing or other resistances).

I already know the basics of heat stroke and symptoms, but nothing I find helps me figure out how quickly the human body absorbs heat from the environment (without complex math that is seriously not my forte).


Let's paint a picture, and see if that helps illustrate the nature of the question.

Person A is a soldier, so we can assume fit, and in the desert. Minimal humidity. Gentle breeze. No water to re-hydrate.

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    $\begingroup$ This is going to be very dependent on the details of the heat, how applied, the person, their health, humidity and how they can hydrate. There's no single answer for this, IMO. $\endgroup$ Sep 20, 2021 at 22:49
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    $\begingroup$ Hello Alexandra, welcome to Worldbuilding. When you have a moment, please take our tour and read through the two Help Center pages shown here: help center, and help center. It'll help you understand how the site works. As for your question, let me give you some insight, while living in Finland I regularly enjoyed Sauna at 110℃ for periods up to 45 minutes. Yup, it's honking hot, but it's completely survivable. My point? Touching a stove top at 110℃ would burn you instantly and walking through a desert very long would be horrific. (*continued*) $\endgroup$
    – JBH
    Sep 20, 2021 at 22:55
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    $\begingroup$ ... meaning how the heat is transferred is incredibly important. It also matters what kind of shape the person is in. Back then, I was young and in great shape. I suspect I'd last about 10 minutes in the same sauna today. Also, I was buck nekid in sauna, but a person swathed in clothing that kept the sweat close to the body would suffer a lot more. Conclusion: there's no single right answer, but the harder it is to evaporate the water from the body, the higher the fat content of the body, and the older the heart of the victim, the shorter the period of time they'd last. $\endgroup$
    – JBH
    Sep 20, 2021 at 22:59
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    $\begingroup$ @AlexandraWilliams Worldbuilding.SE has overlap with Physics.SE, as with Biology.SE. The biggest difference is that if you ask here about human temperature survivability you are often going to get longer answers that may include advice for how your soldier might lengthen their survival with skills taught in the army. That is why it is welcome to provide worldbuilding context - tell us about the problem's background, and also your purpose with the scene or story element. Contrasting; on Biology.SE the same question will get you factual no-fluff answers linking to peer-reviewed research papers. $\endgroup$
    – KeizerHarm
    Sep 20, 2021 at 23:39
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    $\begingroup$ @AlexandraWilliams If I give all those specifics, isn't this going to just get flagged as 'story specific'? It's the other way around. The more details you give us (e.g., the more world rules or circumstantial conditions you enumerate) the less likely the Q would be closed as too story-based. It's when you leave those circumstantial issues to our imagination that you risk closure (hence the VTC reason "needs details"). $\endgroup$
    – JBH
    Sep 21, 2021 at 2:52

1 Answer 1


An hour to hours.

Saunas are routinely 90C or above, and people can sit in them for a while. 75 is pretty low, and with low humidity you can sweat off the heat.

It'll be unpleasant, especially if you're not used to it, but you'll live till you start getting dehydrated. Then you'll get heat stress, heat stroke, and death.

If you adjust the temperature to 100-105 then it'll be enough to disable a fit young adult in a few minutes.

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    $\begingroup$ +1. At 75 C, and young and healthy subject, dehydration will be the main issue. $\endgroup$
    – Alexander
    Sep 20, 2021 at 23:08
  • $\begingroup$ That's kinda the issue I'm having. So, what temperature would you say becomes hazardous to a (fit) person's health where it becomes dangerous within minutes? $\endgroup$ Sep 20, 2021 at 23:12
  • $\begingroup$ Sorry, I'm kinda nervous and I don't think I'm asking the question right. But I'm also trying to not make this weird or entirely about my story either. $\endgroup$ Sep 20, 2021 at 23:13
  • $\begingroup$ 110 C ish is where world record people put the temperature at, with decent humidity. The best one last 15 minutes, the worst just a few minutes. 100-105 is probably appropriate for someone who isn't elite. $\endgroup$
    – Nepene Nep
    Sep 20, 2021 at 23:14
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    $\begingroup$ Thank you so much! $\endgroup$ Sep 20, 2021 at 23:17

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