I like swimming, and am fairly fit as I have been going to the gym for a couple of years (nearly.) However, I find when I swim, I get out of breath really quickly, much more so than when in the gym, and find it hard going. I was in the doctors recently, and there was an article in a health magazine about swimming, but I got called through before I could read it. Can anyone explain to me how to develop a good breathing technique to enable me to swim effortless lengths?