[Jacki Willenborg]

Jacki Willenborg  asked the Naked Scientists:
   
Is there such thing as getting brain damage from too long of exposure to too low of temperatures?
 
Jacki

What do you think?

[Magnus W]

Not necessarily, only if blood flow and thus oxygen supply gets to low. And of course if ice crystalls begin to form you definetly will get brain damage.

In a real life senario if you get very hypothermic I dont think that you would survive temperatures low enoght to couse brain damage since blood flow to the brain probably is one of the last things to fail

[Mazurka]

The effects of hypothermia are to a certain extent dictated by the circumstances surrounding the cooling.

There is the case of Anna Bagenholm where the rate of extreme cooling and careful warming lead to survival after 80minutes trapped under ice with no measureable brain damage (see http://en.wikipedia.org/wiki/Anna_B%C3%A5genholm for summary or google for interviews etc.)

Hypothermia is increasingly used therapeutically trigger the body's mechanisms to miminise effects of blood starvation (typically after heart attack)

Unlike hyperthermia - where brain damage can occurr as proteins and cells are denatured due to heat,  the main risks to the brain in hypothemia are reduced oxygen supply although it is most likely that the person someone has entred circualtory arrest.

Myths surrounding hypothermia due to immersion in cold water are thoroughly debunked in the excellent book "Essentials of Sea Survival” by Mike Tipton and Frank Golden.