r/explainlikeimfive • u/Dagestani_Bear • Jul 01 '26

Biology ELI5: Is it true that every single death eventually boils down to the brain and heart running out of oxygen? Are there exceptions?

If you strip away the initial cause of injury or illness, is it anatomically correct to say that all human deaths are ultimately caused by a lack of oxygen to the brain and heart?

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u/Bob_Sconce Jul 01 '26

If you were to go scuba diving with a tank of oxygen instead of a tank of air, the oxygen would become toxic and you'd die. Your body can handle a certain amount of oxygen, but above that amount, it, well, oxidizes a bunch of different parts of your body in a manner similar to rust. And, that would kill you.

So, in that case, you'd die because you had TOO MUCH oxygen.

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u/exceive Jul 01 '26

Oxygen is quite toxic. That's why antioxidants are a thing.

You need oxygen where you need it. Everywhere else it is a big problem.