Naked Science Forum
General Discussion & Feedback => Radio Show & Podcast Feedback => Topic started by: Evan Stanbury on 24/04/2010 12:30:03
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Evan Stanbury asked the Naked Scientists:
Helen's answer said, in an aside: "Submariners are trained to ...hold their breath ..to swim ... up from the bottom".
I saw a TV show of submariners training for emergency exit, and they were told to breathe out, all the way up, otherwise they would have severe lung/throat problems.
Before escaping, they have to equalise pressure in the escape airlock with the outside (much higher) water pressure, by letting in the outside water.
This compresses the air in the airlock(making their ears pop), and giving them several times the usual volume of air in their lungs.
They need to breathe out all this excess air on the way up (ears pop again), so they equalise pressure when they reach the surface.
The short time at increased pressure doesn't give much time for nitrogen to dissolve in their bloodstream, and protects them from the bends.
PS: I really enjoy the show (http://www.thenakedscientists.com/HTML/podcasts/)!
What do you think?