Originally Posted by Penguin
Something that made a noticeable difference for me:
Don't forget to exhale. This should be one of your foci. You can't suck in a lungful of fresh air if you are still half full of stale air.
Start your exhale, at the very latest, when your body begins the last rock from left to right before you inhale on the right.
Better yet exhale with the exertion of each arm stroke or, continuously, as soon as your face re-enters the water.
I, too had multiple issues hindering me, and getting me short of breath, but luckily, unknown to me, the greatest one was just involuntary tension in my chest -- I had actually sorted out the worst of my other problems before that. So just 1 or 2 weeks before my first Half Ironman last year I got the hint on this forum site to start exhaling through my nose as soon as I put my face back down in the water after taking (each) breath. The trick is to to relax your chest and your larynx (throat) to do a long slow continuous exhalation, trying not to speed up or slow down the smooth trickle of air coming out your nostrils, and to time it just right so that when it comes to your next breath you just have to blow out a slight extra bit of air to empty your lungs at the moment that you turn for air.
Maybe a bit of practice standing in the shallow end bent over with your face rotating in and out of the water might help.
It sounds more complicated than it really is to do it. The relaxing effect of opening your throat and listening for the "bubble-bubble" sound coming out of your nose and keeping that sound level as even as possible (and maybe looking at the size of the stream of bubbles) worked right away to relax my chest and throat muscles, and stopped my shortness of breath, almost like magic. Even if I forgot, and got distracted, and got short of breath again, all I had to do was to focus on slow, even nasal exhalation, and within 1 or 2 breathing cycles I was relaxed again. Just in time to be ok for the race!