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

Partly, it’s that brain work burns a lot of blood sugar. Willpower has been linked with blood sugar, and willpower is a large part of focus. Eat regularly when you’re studying, and eat things that will keep your blood sugar from spiking (e.g. nuts, beef jerky, maybe fruit if you don’t overdo it).

(Source: “Willpower” book by Baumeister and Tierney)