What causes our brain to get “tired” and lose focus when thinking hard for extended periods of time like studying or thinking through a difficult concept?

Question

What causes our brain to get “tired” and lose focus when thinking hard for extended periods of time like studying or thinking through a difficult concept?

In: 120

Answer 1

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Answer 2

the way i understand it is that our muscles can’t handle continuous strain and neither can our brain. it needs rest just like muscles do

Answer 3

Loss of energy if you keep refilling your brain with sugar every 45minutes to an hour it should help