well if you are into streching yoga does the trick , or you can try holding your breath for up to a minute taking deeper breath everytime for up to 10 minutes just make sure you do it a minute at a time. if you can hold it for a minute do not try to over do it or you will feel nothing but light headed. practicing this exerise increase the lengh of your breathing underwater.
Do middle or long distance running routinely. It’s what I do.
well if you are into streching yoga does the trick , or you can try holding your breath for up to a minute taking deeper breath everytime for up to 10 minutes just make sure you do it a minute at a time. if you can hold it for a minute do not try to over do it or you will feel nothing but light headed. practicing this exerise increase the lengh of your breathing underwater.
before you swim, warm up your lungs by breathing bubbles under the pool and coming up, at least ten times or so. then start swimming long distances.
i had your problem once, and i did the aforementioned action and i can hold my breath longer than before.
good luck.