A breathing technique Wim Hof Method is so powerful and effective.
It is known as a method to open the pineal gland that is a myterious organ. Basically it secrets sleep hormone melatonin which regulates your sleep cycle.
You can find a lot of information about pineal gland and its functions.
There is an app to practice Wim Hof Method by Wim himself.
Here are my records:
Today I could hold my breath for 3 minutes. Holding breath incurs fear to die but you can increase the duration step by step by overcoming the fear!
When you practice the Wim Hof Method, you feel electricity as well as light in your eyes. It is sensational experience.