Deep vs shallow SPORTS diving... which is safer?

[boulderjohn]

I think it is important to recognize that the terms deep, shallow, short, and long are all relative. The OP asked the question in terms of recreational diving, and there is a world of difference between a deep recreational dive (100 feet) and a deep technical dive (300 feet).

 

[Duke Dive Medicine]

Right. Part of the OP's question was about the belief that "deep and short" is "safer" than "long and shallow", I'd say it's about trends rather than specific depth and times. Those plots could show the trends as per the current models and we could see if they match the belief. We do trust the models on real dives to real depth, so why not trust them on trends as well?

I see what you're saying. By model I meant the probabilistic model that was used, the way that the pDCS for the plots was derived. It's based on the data from hundreds of actual dives, with outcomes (+ or - DCS). We tested six decompression algorithms IIRC. We plugged a series of depths and bottom times into the decompression software, it gave us deco profiles, we sent that data to Keith Gault at the U.S. Naval Experimental Diving Unit and he plugged it into the modeling software.