Wouldn’t it make more sense to get as much oxygen to the brain as you could?
In: Biology
Just to answer your question about oxygen, your body actually uses next to no oxygen to lift a heavy object. You use something called anaerobic respiration which doesn’t use O2. You would on the other hand, want to breathe in as much as possible if you are lifting light things over and over
Holding your breath allows you to brace your core muscles which provides you a foundation to press against.
Because doing so expands your ribcage and stabilizes your torso, giving your core muscles greater leverage to flex against when they’re working.
I imagine it’s harder to focus on two things at once so body chooses one. And you breathe before a heavy lift so it’s not like you don’t have oxygen available.
It’s called the [Valsalva maneuver](https://en.wikipedia.org/wiki/Valsalva_maneuver).
It creates pressure in your abdomen which otherwise would be loose and flexible.
Like the difference between an unopened can and an empty can, the unopened can has far more structural stability, but is inflexible.
When you lift something heavy you lose much, much less energy through a taught, inflexible core, allowing you to generate more power. Also it is much safer for your spine to remain in a neutral position under load, rather than flexing and twisting under load.
A significant part of weight lifting is learning to optimize this ability.
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