I think a 45 second exposure would cause permanent brain damage, just as the bends can cause.<br /><br />Even repeated exposure to changing pressure within accepted 'safe limits' can cause permanent brain damage
brain damage in divers.<br /><br />Climbers of Mt Everest get permanent brain damage from exposure to the 0.2 atm of pressure:
low altitude brain damage. <br /><blockquote><font class="small">In reply to:</font><hr /><p>Acute exposure<br />Beginning with the notorious balloon flights in the latter half of the 19th century (Glaisher et al., 1981), an extensive literature describes not only such dramatic but also subtler effects of hypoxia on the central nervous system. Investigators have documented decrements in performance on a variety of neuropsychometric tests after sudden exposure to even relatively moderate hypoxia (2000–4500m). The literature has been reviewed by Stickney and Van Liere (Stickney and Van Liere, 1953), Tune (Tune, 1964) and, more recently, by Ernsting (Ernsting, 1978). One response to acute hypoxia is slowed performance, particularly on more complex tests of cognitive and motor function. While error rates also increase, a number of investigators have suggested that slowing might be a strategy designed to minimize mistakes. Changes (in a visual-positioning test performed during light work) have been reported at an altitude as low as 1500m (Denison et al., 1966). These changes with acute hypoxia are evidence that even modest levels of hypoxia can impair brain function. <br /><br />Sustained hypoxia<br />The history of Mount Everest climbs is replete with anecdotal accounts of cognitive impairment of various forms, dating from the early attempts in the 1920s and 1930s. ‘Mental laziness’, i.e. a disinclination rather than an inability to perform mental work</p></blockquote> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>