Mike_Tipton

You are better off out of the water than in it. Water removes heat from the body much quicker than air and humans cool about 5 times faster in water compared to air at the same temperature. PS. Rose held her breath for 35 seconds in the film (Titanic) under ice cold water - I doubt this is possible.

Standard 50% survival times are 1h @ 5°C, 2 @ 10°C and 6 @ 15 °C. Enormous variation between individuals depending on external (e.g. sea state) and internal factors (fitness, fatness, nutrition etc). Also these curves tend to ignore those that die in the first minutes from cold shock (up to 60% of deaths in cold water). This makes estimating survival time as much "art" as "science" and SAR times are lengthened considerably to account for this variation. The large number of death from cold shock is the reason the RNLI Respect the Water campaign focuses on this period of immersion and encourages "float to live" and "fight your instincts". https://www.respectthewater.com/?utm_source=ppc&utm_medium=search&utm_campaign=rtw_2018&gclid=EAIaIQobChMI7oW7zrL-3AIVzpPtCh12oAsTEAAYASAAEgK_H_D_BwE

I have not heard of that as a way of reducing cold shock. I would recommend keeping your airway as clear of the water as possible when you have no control of your breathing. Thank you for supporting the RNLI.

They are cold habituated - see other answers.

I have read the Alexander report on the research at Dachau, I have visited Dachau twice with colleagues. We did a Timewatch TV programme on this subject several years ago (no longer available). When asked, survivors of the concentration camps were happy to have the data used for the benefit of mankind. This has tended to be done but without referencing the researchers. https://www.ushmm.org/wlc/en/article.php?ModuleId=10005168