Gary wrote:
[snip]
I just spent a little time researching freediving. You are right.
Expert freedivers can force air into their ears to relieve the pressure
as they descend. It is what limits them from greater descents but they
can force what little air they have (at depth) into their ears to
relieve the pressure...... somewhat.

You win.

we all win, i learned a lot

i have a few freediving books here that are terrific. one especially
that stands out because of the photos and just sheer lunacy is
"bluewater hunter and freediving" by terry maas. these are folks, i
kid you not ... who go out into the middle of the giant ocean, put on
wetsuits, grab their spear guns, and go freediving for hours at a time.
their goal ? to shoot giant fish even bigger than they are while at
the same time not getting eaten by sharks. and yeah, sometimes they
fail and get eaten by sharks!!! there are white sharks there! they
are in competition for the same food! apparently it's not that unusual
to shoot a fish and have sharks eat it before you can even get it on
board! lol. just crazy. beautiful book, highly recommend it.