system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What does adrenaline do with your brain that you feel sharpend and stronger?
gpt
When your body releases adrenaline it's because your brain has sent out an alert that you need to prepare to either stay and fight or run to safety (flight). You brain prepares your body by increasing your heart rate, so that your core organs are functioning at their highest level of performance. Your brain will also increase your vision to be focused on what is straight ahead of you (tunnel vision). Also, your brain increases your respirations to increase oxygen flow to your brain and organs.
It's interesting to note that when this fight or flight trigger is misfired from your brain, when there is no need to fight or flee, it is was millions experience as a panic attack. The physical symptoms you experience during a panic attack are due to the adrenaline released by your brain to prepare for fight or flight. Beta blockers have been found to assist in decreasing the amount and frequency of adrenaline in people who suffer from panic attacks.

Oh and the sharper vision is to assist you in your escape. For those in the panic attack category, they report feeling as though they have tunnel vision or that things appear dreamlike or surreal.

Hope that helps to answer your question.