system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 - Why does a stressful day at work make you both mentally and physically exhausted?
gpt
The brain requires energy to work just like your muscles do, it actually uses more energy than any other organ, using up to 20 percent of the body's total. A stressful day at work is going to result in long periods of ~~high~~ brain activity which is going to drain your body's energy as a whole.