[naiad]

I don't get any reliable warning. Sometimes there is a feeling that the urge to breathe fades away, or becomes a nice feeling that I don't want to stop. Then I know that I am close to the limit. Sometimes there is no warning at all. I have never had any disturbances of vision.

There are certainly lots of factors that affect how long you can hold your breath. I have hardly ever blacked out doing my longest times or distances. It has mostly been because of doing something different from usual, which I am not used to.

Lucia