The natural process of breathing is something that we never control and think about, but there are so many secrets hidden in this process. I have had a chance to interprete a lecture in meditation and feel on my own experience how different breath techniques influence our organism. So, I'd like to share some of the secrets that opened to me.
First of all, be don't breath with both nostrils all the time. Check your breathe and you'll realize that the air is leaving your body through one of the nostrils while the other "rests". They change every 1.5 - 2 hours and are responsible for different types of energy and that is really amazing. Still, there are some moments when we breath with both nostrils and these episodes are very short. Jogi people say that during such episodes our sushumna opens and that activates some hidden resources. I don't want to go deeper into this very question, if you're interested in the subject you can google it and read more information about sushumna channel.
I am sure that you've noticed this effect if you were ill and you couldn't breathe normally (one of the nostrils was blocked). But then suddenly the breathing nostril changes and the block overgoes to the other part of your nose. Everyone has noticed it, though really few care about it.
There are some breath techniques that can help either to cool or to heat the human body and there's a scientific exploration for these two effects. If you breath in air through your mouth with your tongue rolled, and breath out through the nose, you'll feel that your body is getting cooler. Our tongue is a unique muscle and it becomes cool very fast cooling the whole organism (actually, animals like dogs use the same technique to cool their bodies). If you want to heat up your body, you should make some fast and noisy inspirations and expirations and then hold your breath for 15-20 seconds (don't make your lungs burn and suffer). The pressure inside will make your body feel warmer.
Another thing is that depressed people can't breathe normally. There's some disbalance in their mind and their body and as the result the pressure comes. Depressed (really depressed) people pull in the stomach when breathing in which will never happen to a healthy person.
How can we explore space and ocean if we haven't yet explored our own body? That is knowledge and that is amazing. Observe your body and it will definitely open some more secrets for you.
Yours,
Anastasia