Why is the way you breathe important?
Obviously you need to breathe in as you are swimming. What is not always realised is the importance of breathing out! If you do not breathe out fully you will not be able to inhale the amount of air that you need and you will quickly tire. Efficient breathing does not disrupt your stroke.
The perfect stroke – breathing!
You should breathe out fully while your face is in the water through your mouth and/or nose. You should have expelled all the air before you turn your head to breathe. Your head should rotate gradually in line with body as your arm is pulled back. The breath is taken at the end of the push phase when your body is fully rotated.
There should be no lifting of the head. As your body and head rotates, one eye and one ear should stay in the water and you should breathe in the small bow wave that is created by your head as it moves through the water. Return your face quickly to the water so that it is back to a neutral position as your arm reaches your head during the recovery phase.
You can breathe every two strokes (ie., always to the same side), three strokes (bilaterally), or four strokes and so on. What is best for you will depend on your lung volume and also how hard you are swimming. However, there are big advantages to being comfortable breathing bilaterally. Importantly it will allow you to maintain a well balanced stroke since you will need to develop good long-axis body roll to both sides. Bilateral breathing is also useful in open water swimming since it allows you to see things on both sides. Breathing exclusively and effectively to either side is particularly useful for triathletes. Swimming in open water brings particular challenges like the need to breathe on the opposite side to waves.
What can go wrong
Breathing: Not breathing out underwater
If you do not fully breathe out underwater then either you will have to expel air once you have rotated your head and before you take a breath, or you will have to take a small breath because your lungs are not fully empty. Either way, you will find that you do not get sufficient oxygen into your lungs on each breath and you will tire very quickly.
Breathing: Lifting head when breathing
Every action has a reaction! If you lift your head when you breathe your hips and legs will drop as a direct consequence. Your hips and legs will no longer be following your shoulders through the hole – you will no longer be streamlined in the water! It is very common to see a swimmer use their extended arm (non-breathing side) to push down on the water and lift their head. If you do this then your stroke from this arm will be ineffective as there will be no catch phase.
Breathing: Cannot breathe bilaterally
The ability to breathe comfortably bilaterally is important to develop and maintain a well balanced stroke where your right arm pulls as effectively as your left arm. You often find that a swimmer that breathes consistently only to one side has little rotation to the non–breathing side and that the arm stroke on that side can be weaker and poorly formed.