16 January 2012

How to survive in cold water

If you fall into cold water, you can delay the effects of hypothermia and increase your chances of survival with these tips.


If you fall into cold water, you can delay the effects of hypothermia and increase your chances of survival as follows:

  • Keep as much of your body out of the water as possible. If you can, pull yourself out of the water onto a floating object.
  • The more energy you use in cold water, the more your body cools. If you can't climb out of the water, conserve body heat by staying as still as possible and reducing the body area exposed to the water. Protect your critical heat loss regions: head, sides, armpits and groin. Don't try swimming unless shore, or an object you can get onto, like an overturned boat is nearby and you can definitely get to it.
  • If you are wearing a lifejacket, you may be able to use the Heat Escape Lessening Posture (H.E.L.P.) to reduce heat loss: hold your arms tightly against your sides and across your chest, hold your legs together and up toward your chest.
  • In the case of two or more people wearing life-jackets, huddle together to conserve body heat and increase your visibility for rescuers.

The human body and cold water: some interesting comparative temperatures


Core temperature of the human body.

35°C If your core temp. drops below this, you have entered the deadly realm of hypothermia.
30°C (early 30s)  Temperature of the water in a "hot swim" e.g. in Lake Malawi.
27°C The indoor pool at your gym.
22°C Water off Muizenberg beach in summer.
18° English Channel, summer
15°C A cold shower.
11°C Swimming to Robben Island (on a bad day).
5°C Water temperature when the Titanic sank. Most of the deaths were due to hypothermia within an hour of immersion in the sea.
0°C Fresh water freezes. The human body can't withstand water temperatures below this for much longer than about 15 minutes, at most, before unconsciousness or exhaustion. Death occurs in under 15 to 45 minutes.
-1.7°C Water at the North Pole. The body loses heat in cold water much faster than in cold air (remember the end of Titanic, when Kate Winslett survives by reclining on a piece of flotsam, while Leonardo di Caprio stays in the water and cops it?), and a moving body loses heat much faster than a stationary one. Exercise pumps blood to your extremities where the water rapidly cools it.
-1.8°C  Salt water freezes

Coldest sea water ever measured, in a stream under a glacier in the Antarctic in 2010.

Compiled with assistance from Lewis Gordon Pugh

- Olivia Rose-Innes, EnviroHealth Editor, Health24, updated January 2012

Read more:
Meet the Iceman. Lewis Pugh explores the coldest limits the human body can endure.


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