They died before they had a chance to use almost any of their oxygen. But how much time could more air by you when you have no food or water and it's 39 degree

They died before they had a chance to use almost any of their oxygen. But how much time could more air by you when you have no food or water and it's 39 degrees? Do you want that time if you're on the bottom of the ocean and they can't extract you?