Conventional swimming instruction will always advise you to inhale through your mouth. I went on holiday with my brother about 15 years ago and he asked why this was. ‘You can get more air in through your mouth and it accommodates both water and air,’ I told him. Ignoring this, he proceeded to do a nice breaststroke breathing though his nose, for the rest of the week.
It’s perfectly possible to do it if you swim slowly and in particular if you slow the breathing phase down. So why is it a good thing to try?
Mouth breathing isn’t something that anyone would recommend you do in any other physical activity. You can get more air in quickly through the mouth, yes, and if you’re swimming fast, you do have to do this. But mouth breathing generally is part of a whole pattern that it’s better to avoid, one which is associated with a panic and gasping reflex. If you can breathe in through your nose, it helps you prevent this total pattern.
Because of anxiety about getting air, we tend to rush the breathing phase, waste energy and tense up getting the head out. We generally overdo the inhalation and breathe from the top of the chest instead of the back. Breathing through your nose helps prevent all of this.
It’s challenging to breathe in through your nose. You have to be well coordinated enough in the water, balanced enough, to slow the breathing phase down. If you’re a good enough swimmer to slow things down and breathe through your nose, you have nothing to lose by trying it.
If you’re not well coordinated enough in the water to do it, it’s worth working on your basic coordination so you are able to slow down the breathing phase and find balance. Otherwise, your stroke will run away from you and you won’t get as much out of being in the water as you could.
Instead of trying to swim as fast as possible with an inadequate stroke, a lot of recreational swimmers would do better to work on finding balance in the water; to see the whole business of swimming as more like yoga or meditation than competitive sport.
You’d never be asked to breathe in through your mouth in those disciplines, would you?