Why does learning something new exhaust you?

1 year, 8 months ago

Because your brain has to construct structures within itself to faccilitate a new skill's ease of use, and this exhaustion is your brain's method of communicating that it is overwhelmed.
Unless you mean pre-emptive exhaustion, for which case it is the same as how you can feel tired when you think about going to the gym. Your body & brain wants to save you from unnecessary calorie expenditure.