Recently, I was asked to give some swim technique pointers regarding breathing and being relaxed in the water -- I got on a roll and wrote this extended answer, so I'm just posting it. From years of watching people swim at all levels, it seems like this is a fairly common problem among novice swimmers. I see them start their races with quite a few great strokes. Then they have to breathe. Their whole body stiffens causing their hips sink. The body area opened up to drag during the breath brings them to nearly a complete stop. Often by the time they get their body back into proper position, they need to breathe again. As the swimmer becomes more and more tired, breaths become more frequent and they cease returning to proper position even between breaths. While this is a slight exaggeration for most back of the pack swimmers, it helps illustrates what improper breathing technique can do to your swimming.

Most breathing and body position problems are caused by improper head position. During non-breathing strokes, it is easy. The head looks about halfway between down and forward (erring on the down side) depending on your body’s center of mass. It is simply a matter of finding that point where your hips just float up and committing it to muscle memory: if you look up a little more your hips sink, if you look down any more you are burying your head causing unnecessary drag. But that is not the issue at hand. If the swimmer above were given a snorkel so he didn’t need to interrupt his rhythm, he would be able to maintain good technique almost indefinitely.

It is necessary find a system of breathing that does not change your body position and therefore interfere with the flow of your stroke. To maintain a constant body position, one must keep the head as still as possible. Therefore, on breathing strokes, it helps to tip your head sideways and back so your chin points toward your shoulder. This brings your mouth upward toward the depression of the water’s surface caused by your body’s rotation, which many swim coaches refer to as the ‘hole’. It also lowers the top of your head so that there is a minimal net change of head position.

A more common even among better swimmers but slightly less serious problem is hanging out on your side with your mouth up in the air for too long throwing off your rhythm that way. This mistake also forces the opposite hand to cross over to maintain balance causing the hips to slip to the side. To maintain the most effective form, you head should start turning when your hand leaves the water and your face should be back in the water by the time your hand passes your ear. That is a much shorter time that most of us are used to. Therefore it is necessary to blow out all of your air underwater, as you will only have time to breathe in.

How often should you breathe? To perform aerobically for endurance events, you need to breathe one out of three strokes (a coach once gave me some scientific data supporting that based on ideal turnover rates and typical aerobic oxygen consumption, but I have since lost it and only remember the advice). That means you should have a pattern of one two breath, one two breath, etc. or one two three breath, one breath, one two three breath, one breath, etc. I use the alternate breathing pattern for training, as is helps keep my stroke even and balanced and more importantly helps prevent shoulder injuries. However, I do favor a particular side, so I mostly use the second pattern for racing. Some people that should take fewer strokes per breath are raw beginners who find themselves going anaerobic every three and people with particularly slow turnover rates.

During the excitement and scramble of a racing situation, it is basically impossible to focus on technique. Therefore it is necessary to swim often, particularly during base when its cold and your biking and running are limited anyways, and commit all technique to muscle memory so you can forget about it and just swim in a race. That is why it is better to get in the pool for many short workouts per week rather than one or two longer ones (do a long workout every once in a while for endurance though). Some helpful drills for breathing and body position:

-breath every stroke every side watching your hand come around (very important and helpful drill. Makes it necessary to exhale underwater, its harder to linger on the breath, make sure your face gets in the water when your hand passes it)
-swimming with a pull buoy especially during your warm-up gives you body a sense of what it feels like to have proper body position and you can practice front end technique without worrying about kick
-flutter kick on your side with the bottom arm mostly extended (On your side slightly leaning towards your front. You should never completely stretch out your arm as that drops your elbow and throws you off balance. Your top and should rest on the front of your thigh. If you find yourself making a large sculling motion with your front hand, something is wrong with your position. Relax and let your body find the natural balance point.)
-flutter kick switching sides every 8 kicks (same as above switching sides. Concentrate on a quick switch (shifting balance) and keeping your body on one line throughout the switch i.e. don’t let your rotating axis bend or shift, remember all rotation comes from your hips)
-hypoxic set #1 modify it to fit your needs and ability but a great set for me is 7 x 200 with 15-20 seconds rest in between breathing every 3, 5, 7, 9, 7, 5, 3 strokes. Good during the base and early build phases of training.
-hypoxic set #2 modify as you will. 8 x 25 no breathing with 20-30 seconds rest. I usually do as many repetitions as I can until I fail to make the 25 without a breath. You will immediately find that it is easier to go slow and smooth. A good set for late build and peak. Do this at the end of a workout immediately preceding your cool down.

The hypoxic sets really help ease the desperation that one sometimes feels for their next breath. This desperation often leads to body stiffness. Also once you try a few 25s no breathing, you will see just how much more efficient it is to be to swim smoothly. If used properly, those sets can be extremely effective in getting you to relax more and finding your most effective cadence. You can probably find diagrams for the drills online somewhere. I am not familiar with the Total Immersion stuff but I’m sure they have good drills as well. As a final note, for a fun test set, I like to challenge myself to swim as far as I can without breathing (safely). My record is 75 yards back in my swimmer days (using flip turns and its closer to 50-60 yards now) – let me know if you can beat it.