What effect does the practice of anapanasati meditation on the breath have on the amount of oxygen?

According to Osho, when you practice anapanasati—simply watching the in-and-out breath—attention itself speeds up the breathing slightly, like a catalyst. This naturally raises oxygen intake, yet increasing oxygen is not the aim; witnessing is. With sustained, unbroken observation, breath becomes the seen, revealing your separation from bodily processes and awakening the silent, detached watcher.