Meditation indeed decrease the consumption of oxygen during the meditation itself. This is experienced by the practitioner.
Science has shown this by doing this oxygen consumption research on the practitioner.
As you can see there, the deeper you are, the less oxygen you intake.
At a very high level, the breathing actually stops.
This is shown by the life experience of Xuyun in this link (Thanks to Nana, very interesting paper)http://www.chibs.edu.tw/ch_html/chbj/22/0619huimin.pdf
On page (60):
"...Testing his breathing with a straw to his nose and seeing no movement, the attendants thought the Master has passed away. However, since his body was still warm and his complexion pleasing, the two attendants kept serving him.
Not until the morning of the eleventh day of the month (April 16th), hearing the Master groan slightly, did the attendants help him up. They told him how long he had been in samadhi in his bed, and the Master slowly told his attendants that while in samadhi he travelled to Tusita Heaven to hear the Dharma...."
Another example is the life of Ajahn Chah. This is told by Ajahn Brahm in his book Mindfulness, Bliss, and Beyond
"...Moreover, in deep jhana, we can experience the breath disappearing altogether (in the fourth jhana) with no danger to life.
During my teacher Ajahn Chah's long sickness, he would often stop breathing. On one such occasion the new nurse on duty became alarmed. He knew that Ajahn Chah must die one day, but he didn't want it to happen on his shift! The attendant monks on duty that night reassured him that Ajahn Chah had done the same many times before and that it was just a sign of deep meditation. The nurse was still worried and so took blood samples every few minutes during the hours without breathing to ensure that the blood was still well oxygenated. After all, as long as there is enough oxygen available in the blood there will be no harm to the body. The nurse discovered that even though Ajahn Chah was not breathing for a long time, the oxygen level in the blood remained constant. In Jhana, the metabolism is so slowed down that you are using almost zero energy. You don't need to breathe...."
Whether your breathing stop or you consume less oxygen, this one comes from the serenity or calmness you do in meditation.
Any samantha meditation (calm abiding) will do.