CathInfo.com

I didn't watch the video you posted but I read a large portion of a book called "Breath" by James Nestor. It deals with breathing properly, chewing our food, etc.In it he wrote the following which I found really interesting and wanted to share:
"In 2001, researchers at the University of Pavia in Italy gathered two dozen subjects, covered them with sensors to measure blood flow, heart rate, and nervous system feedback, then had them recite a Buddhist mantra as well as the original Latin versions of the rosary, the Catholic prayer cycle... They were stunned to find that the average number of breaths per cycle was "almost exactly" identical, just a bit quicker than the pace of Hindu, Taoist, and Native American prayers:5.5 breaths per minute.
     But what was even more stunning was what breathing like this did to the subjects. Whenever they followed this slow breathing pattern, blood flow to the brain increased and the systems in the body entered a state of coherence, when functions of the heart, circulation, and nervous system are coordinated to peak efficiency. The moment the subjects returned to spontaneous breathing and talking, their hearts would beat a little more erratically and the integration of these systems would slowly fall apart...
     It turned out the most efficient breathing rhythm occurred when both the length of respirations and total breaths per minute were locked in to a spooky symmetry: 5.5-second inhales followed by 5.5 second exhales, which works out almost exactly to 5.5 breaths a minute. This was the same pattern of the rosary"

This doesn't really sound to me like a good idea. So you hyperventilate for a while, and then hold your breath for a very long time? And what exactly does this do to your brain? Hyperventilation can cause strange effects in the brain, I think including euphoria or similar mind-altering effects.

Don't play games with your brain. And don't deprive your body of oxygen.

What it actually does is to kind of « reset» your nervous system, which leads to be more relaxed and breath better after. It often happens that during the day we never take the time to breathe well with the diaphragm, and then our brain lacks oxygen, and this exercise gives back the oxygen to our brain that we have not given it because of our bad breathing, which is often due to the stress of daily life. This is the main reason for this practice.