What are the different ways for me to get re-oxygenated?

Breathe = #1: Oxygenation of the blood occurs by the act of breathing. The rate of breathing is controlled by sensors detecting oxygen and carbon dioxide levels. Those who take hydrogen peroxide drops to "oxygenate" themselves are taking oxygen radicals, which damage blood vessels and tissues. If tissues or blood have low oxygen due to diseased lungs or blood vessels, that's another, much longer discussion.