A kundalini yoga breathing practice is called pranayama.
Of all the different yoga types, the yogic scriptures say kundalini yoga is the highest and most powerful.
So what's the biggie with breathe in yoga, martial arts, and eastern culture?
Well simply put, it contains what we need to stay alive. It's not soo much the oxygen according to yogic teachings, but the prana it contains. Prana is the sanskrit word for what we know as mana, psi,chi,bio- electricity and so on. It's life energy, the air is just a means to transport it.
So what do you need it for in magic? Well breathing is intricately connected to our mind. If you're breathe is shallow so is your mind. That's why when you get scared your breathe gets heavier and your mind is in panic mode. We need alot of prana intake to empower our magic, we also need it for our health. If you have too little, much will go to your ritual leaving you drained.
Another point is that most of us breathe WRONG! Shoking, I know hehe. We breathe in a shallow manner that makes our body work harder and organs weaker. Which leaves us prone to stress and less energy.
This wonderful website page mentions how to breathe properly, but you can Google it to see it which might be better. The website is Spiritvoyage.com and the article is " All about Kundalini yoga: pranayama"
I can't post links cuz i don't know how with this phone and some websites mention something that I can't or else lol.
Finally the website mentions various pranayama that help with different faculties like health, immune system, brain hemisphere healing which is huge in magic!!!