I'm not a triathlete (and not much a swimmer either ) but a couple of things did sound familiar. Yesterday I tried to swim a bit in fairly cold sea water, and even though I've got a whole lot better at breathing properly when swimming, the cold def. made me suck in(gasp in water as soon as I'd finished exhaling. Disconcerting.

And cold air on my head in winter makes me get a bit dizzy and disoriented sometimes. It's not unusual for me to get to work in winter and feel like my head's not all there yet.