As a beginner, I'm probably not supposed to disagree with a more experienced diver about such things, but I think I've read enough about these issues to be able to say confidently that ascending faster than 60 feet per minute (while exhaling) puts one at risk of the bends, not of arterial gas embolism. AGE is caused by a lung overexpansion injury, which is usually due to breath-holding.
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I'm going to oversimplify here but: The larger concern with a fast ascent on recreational dive is an arterial gas embolism (AGE) vs. decompression sickness DCS, or "the bends." The "bends" are more typically associated inadequate decompression ("going into deco" and not offgassing appropriately).
You are more than welcome to disagree with me, hey, I'm learning all the time too, I don't get it right EVERY time
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In this case, however, I was VERY specific with my wording for a reason... and I stand by what I said. I didn't say it did NOT put you at greater risk of the bends, I said the larger concern was AGE and the increased risk of the bends is less of a concern. Which, in my experience, is the way it works out in the real world. To reiterate, I was making two points In regards to DCI:
FIRST: in fast ascents in recreational diving the
larger concern is pulmonary barotrauma and AGE... not DCS or the bends.
SECOND: there's no magic ascent rate at which one will contract the bends... yes, should be safe under 60 ft/minute, and no, can't rocket to the surface, but there is gray area in between at which one may or may not necessarily get bent. (my example was 75 ft/minute).
Important to remember - you usually CAN fix bent (at least in most locations), it's my understanding AGE is harder (in many cases impossible) to fix, (so don't hold breath), and MUCH harder to fix drowned - so that gets back to my original point - prevention is the best cure - better not be in the position to begin with!!!
For DAN's view on the subject, see
http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=65
It's an old but good article, this thread made me look it up. One paragraph notes:
Who Gets DCI?Decompression illness affects scuba divers, aviators, astronauts and compressed-air workers. It occurs in approximately 1,000 U.S. scuba divers each year. Moreover, DCI hits randomly. The main risk factor for DCI is a reduction in ambient pressure, but there are other risk factors that will increase the chance of DCI occurring. These known risk factors are deep / long dives, cold water, hard exercise at depth, and rapid ascents.
Rapid ascents are closely linked to the risk of AGE. Other factors thought to increase the risk of DCI but for which evidence is not conclusive are obesity, dehydration, hard exercise immediately after surfacing, and pulmonary disease. In addition, there seem to be individual risk factors that have not yet been identified. This is why some divers seem to get DCI more frequently than others although they are following the same dive profile.[emphasis mine]