Posted by mike on March 10, 2001 at 20:59:34:
In Reply to: Lung Overexpansion Injury posted by Jim Hoffmann on March 10, 2001 at 09:18:36:
Especially with the danger of swells overhead. Last week at Sta Cruz, my computer's ascent rate monitor freaked out and went into the red when a big swell went overhead, while i was firmly anchored to a rock cleaning a scallop. If one is at say, 20-30 feet, then takes a breath as a 4 foot swell passes overhead, then pressure in the lungs suddenly goes up by 13-20% when the swell passes. Even if there was NO pneumothorax or severe AGE, (unlikely IMO /w/ 13-20% pressure change), i'd be willing to bet that there would still be some damage to the gas-exchanging tissues.
yep, unlike N-narcosis, holding one's breath is NON-NEGOTIABLE. It's not theory, it's fact.
upon further recollection of past dives over shallow reefs, with camera, i've held my breath with closed epiglottis, for a few seconds while composing/waiting for the critter to cooperate while small swells have gone overhead. How long does it take for a swell to come and go? Hmmmm, methinks me's dodged a bullet or two <:-(