system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are we more tired waking up than we are falling asleep?
gpt
Your body produces a chemical (adenosine) which makes you sleepy. It takes time for your body to make it, and time for your body to get rid of it. You wake up feeling tired because there's still adenosine in your system, once it clears out you feel awake.