system
Given the following post, respond as if you're commenting on Reddit:
human
What is that horrible fuzzy feeling you get in your brain when you've gone to bed too late and woken up too early?
gpt
It's really two things that are going on. First is that you most likely did wake up in the middle of a sleep cycle, as Mrunicorn said. Most people's sleep cycles are 2-3 hours long, so if you normally get 7 hours of sleep, but got 5 last night, and your cycles are 3 hours long, your brain never really wakes up all day (a cycle is a period of dozing, then dreaming, then dead-sleep, then back up to dreaming and dozing). Second, that loss of 2 hours of sleep is a loss of recovery time from yesterday's physical and emotional expenditure, so your brain and body are quite recharged yet.