# At what water temperature can someone survive indefinitely? **URL:** \ **Category:** Factual Questions\ **Created:** [March 22, 2002, 12:35am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456 "2002-03-22T00:35:49Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![SenorBeef](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senorbeef/32/2220_2.png) [@SenorBeef](https://boards.straightdope.com/u/SenorBeef)\ **Post date:** [March 22, 2002, 12:35am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/1 "2002-03-22T00:35:49Z")
You often hear stuff in movies like “At this temperature, he’ll only be able to survive for 3 minutes”, etc. Is there a guide somewhere about how long a person will survive in a given temperature - and for that matter, how warm does it have to be for someone to be able to survive indefinitely? How much does body fat and physical condition play into this? ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [March 22, 2002, 12:56am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/2 "2002-03-22T00:56:59Z")
Found through [Google](http://wwwl.google.com) searching with terms “hypothermia water chart”: > **[Boat Safe this Spring or Fall – Avoid Hypothermia | Boat Safe | Water Sports,...](https://www.boatsafe.com/boat-safe-spring-fall-avoid-hypothermia/)** > > During the cold weather, hypothermia is a major concern. You need to be aware of the symptoms of hypothermia anytime you’re on or near icy water. Cold temperatures can lead to body heat loss, and severe hypothermia can set in. Death is even a... Hope this helps. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [March 22, 2002, 3:26am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/3 "2002-03-22T03:26:39Z")
I think I would be pretty comfortable with 98.4 degrees. Eventually, my skin would slough off, from causes I don’t think are especially related to temperature. My WAG is: no one can survive indefinitely fully immersed in ANY temperature water. ---
**Author:** ![SenorBeef](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senorbeef/32/2220_2.png) [@SenorBeef](https://boards.straightdope.com/u/SenorBeef)\ **Post date:** [March 22, 2002, 5:15am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/4 "2002-03-22T05:15:04Z")
Well, I don’t mean indefinitely then. But, say, for the purposes of a 4 hour swim, what’s the lowest temperature at which someone would not be in physical danger or experience hypothermia? ---
**Author:** ![SenorBeef](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senorbeef/32/2220_2.png) [@SenorBeef](https://boards.straightdope.com/u/SenorBeef)\ **Post date:** [March 22, 2002, 5:15am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/5 "2002-03-22T05:15:34Z")
The chart is handy, thanks. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [March 22, 2002, 11:11am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/6 "2002-03-22T11:11:41Z")
According to Peter Wheeler, an evolutionary biologist, the average naked adult male can survive in water indefinitely at 78°F assuming he has access to food with which to generate body heat. In air, which conducts heat away from the body much more slowly, he can survive indefinitely at 36°F, again assuming access to food (and no wind). Children, and especially babies, are more susceptible to hypothermia because they can’t generate body heat as fast. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [March 22, 2002, 11:43am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/7 "2002-03-22T11:43:08Z")
> [@](#): > > \*Originally posted by bibliophage \* > \*\*According to Peter Wheeler, an evolutionary biologist, the average naked adult male can survive in water indefinitely at 78°F assuming he has access to food with which to generate body heat. In air, which conducts heat away from the body much more slowly, he can survive indefinitely at 36°F, again assuming access to food (and no wind). Children, and especially babies, are more susceptible to hypothermia because they can’t generate body heat as fast. \*\* Is there something online about this? I’m curious about the effect of long term immersion on the skin – somehow I think it would occacionally need to be dried off. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [March 22, 2002, 6:38pm UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/8 "2002-03-22T18:38:33Z")
Wheeler was discussing only survival with respect to temperature regulation. I don’t know about the effect of immersion in water itself, but it would be interesting to find out. ---
**Author:** ![Fiver](https://avatars.discourse-cdn.com/v4/letter/f/e274bd/32.png) [@Fiver](https://boards.straightdope.com/u/Fiver)\ **Post date:** [March 22, 2002, 8:10pm UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/9 "2002-03-22T20:10:33Z")
**bibliophage** In air, which conducts heat away from the body much more slowly, he can survive indefinitely at 36°F, [/QUOTE] You\*\* try surviving indefinitely naked at 36°F, sport. Me, I’ll be inside next to the fire in my union suit. And **yojimboguy** , you would get too hot at 98.4 degrees and probably dehydrate and get heatstroke after a while. Our bodies aren’t in thermal equilibrium when ambient temperature equals body temperature, because our bodies _generate_ heat and can dump it more easily into an environment cooler than we are. I think a fellow named [Cecil Adams](http://www.straightdope.com/classics/a3_059.html) has said a thing or two about this. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [March 22, 2002, 10:24pm UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/10 "2002-03-22T22:24:27Z")
> [@](#): > > \*Originally posted by Fiver \* > …And **yojimboguy** , you would get too hot at 98.4 degrees and probably dehydrate and get heatstroke after a while. > > Our bodies aren’t in thermal equilibrium when ambient temperature equals body temperature, because our bodies _generate_ heat and can dump it more easily into an environment cooler than we are. > > I think a fellow named [Cecil Adams](http://www.straightdope.com/classics/a3_059.html) has said a thing or two about this. \*\* I figure because heat transfers so much more efficiently through water than air, a slightly-cooler-than-human-body-temperature “lake” is all that’s needed. Just to be safe, I’ll settle for 97 degrees. I was looking at the upper (more comfortable :)) range of survivability. But I’m still looking for info about effects of long term immersion. Suppose we all agreed on a comfortable temperature, and we design a special apartment for our hardy volunteer. Only the head goes above the water, with an occasional arm-raise for the snack tray (and somebody figures out a miraculous waste removal system). Throw in some harness/mask to prevent drowning while sleeping. **Could** a person live indefinitely this way? Water **IS** “the universal solvent”. ---
**Author:** ![jk1245](https://avatars.discourse-cdn.com/v4/letter/j/49beb7/32.png) [@jk1245](https://boards.straightdope.com/u/jk1245)\ **Post date:** [March 22, 2002, 10:50pm UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/11 "2002-03-22T22:50:30Z")
I think the temperature question has been pretty well handled. As to the other question (could people survive in water indefinately), I beleive the answer is no. I recall reading an account of a US ship sunk in WWII where the surviving sailors were in the water for a several days before being rescued. When rescuers finally came and started pulling people aboard, they had to be careful so as to avoid “pulling their skin off as a glove is removed from a hand” (that phrase sticks in my mind). Sorry, I don’t have a cite. Granted, that was in salt water, which no doubt sped the process up, but I’m guess a week or two would be about it (total WAG based on the previous story) ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [March 23, 2002, 12:30am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/12 "2002-03-23T00:30:19Z")
I think a baby does pretty well inside a womb, which would be around 98 deg, I suppose? ---
**Author:** ![Forbin](https://avatars.discourse-cdn.com/v4/letter/f/5e9695/32.png) [@Forbin](https://boards.straightdope.com/u/Forbin)\ **Post date:** [March 23, 2002, 1:50am UTC](https://boards.straightdope.com/t/at-what-water-temperature-can-someone-survive-indefinitely/99456/13 "2002-03-23T01:50:48Z")
The case of [George Gay](http://www.ussyorktown.com/yorktown/georgegay.htm) may be informative. He was shot down during the battle of Midway, and survived in the water for a day and a night at least. He was injured too. I know this doesn’t directly answer your question, nevertheless, it is informative.