: I have conditioned myself to freedive over many years. I started
: out barely getting past 20 feet. Now I can easily hit 60.
: However, the chance of shallow-water blackout has not changed.
: In fact, shallow water blackout is most common in people who
: freedive all the time and have conditioned their bodies to
: "ignore" the feeling of needing air. I know this is a
: different topic, but I'm relating it to swimming in the cold
: because it's similar in that you condition yourself to go beyond
: where you normally would.

: I'm curious if when people are conditioned to cold water do they
: reach a point where hypothermia still sets in but more rapidly.
: In other words, I wonder if they would go from feeling okay to
: being totally hypothermic with no in-between area like you and I
: would. With shallow water blackout you just go from swimming
: along minding your own business to dead. Boom. You pass out, and
: if not brought to surface in just seconds you will die. The few
: that have survived have said there was no feeling of needing
: air, no warning- just suddenly they blacked out. I wonder if a
: person conditioned to cold would still reach a point where they
: just rapidly hit hypothermia similar to free-divers that black
: out suddenly.

: Cheers,

: Malcolm

Hi Malcolm,
I don't think the two are comparable. With freediving, you're using an oxygen 'reserve' and ignoring the anoxia warning triggers. With cold, it's more where you condition your body to alter its bloodflow patterns somewhat to minimise heat loss. The warning triggers still become as apparent as without any conditioning, which aren't as apparent as you'd think. A lot of people don't actually know what the warnings feel like so aren't fully aware of them when they happen.
Also, long term cold water swimming has an interesting effect, you get fat. :) Similar type of fat that seals have rather than excess-food-fat in that it is laid down fairly evenly over the entire body.

The local lough, Lough Ine, has water temps of about 13C, 55F, now and people swim there for fairly long times without any cold effects. The top few inches of water does get noticable warm by late evening on 'hot' days, though. Oddly, that warmer water feels 'yucky' to me.

Mike Savage
South West Cork