[cdavis]

There are several descriptions under, Frediving training, safety, and another detailed account under Freediving Stories, "Lessons learned in the Bahamas - An intimate account of our most dangerous enemy".

Personally, I've never blacked out, but at about 17, I had several instances of tunnel vision, loss of color vision, etc. Real close to BO, associated with fast repetitive spearfishing dives and hyperventilation. If it hadn't been very shallow, I probably wouldn't be here.

Connor