The most important things required to sustane life are air, food and water. We have a maximum of three minutes without air, being without food mostly depends on how much the body can feed off itself, but being without water usually causes the giving up of the ghost around a week or so at the most. I don't want to test any of those things.
As a child of intense curosity I did try holding my breath to see if it would kill me. It didn't, but I saw gnats behind my eyelids before I stopped and staggered about. Mama slapped my thighs into running. My little brother Buddy decided against his test...
