system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does alcohol make you feel awake at first but then really sleepy at the end of the night?
gpt
Alcohol in the blood at a concentration of <0.02 actually affects the human body similar to the way a stimulant would. Once your BAC rises above that, it has the opposite effect depressing/relaxing/sedating the nervous system. This results in a drop in slowed heart rate and decreased blood pressure.