system
Given the following post, respond as if you're commenting on Reddit:
human
Why am I sleepier when I sleep more?

Why am I sleepier when I sleep like 7-10 hours as opposed to when I sleep 1-4 hours?  When I have 1-4 hours of sleep and then wake up I usually wake pretty quickly and will last through the day but when I get 7-10+ hours and don't wake up by myself (meaning just can't sleep anymore) I feel really groggy the whole day and start zoning out and getting really sleepy.
gpt
Chances are that when you slept for the lesser amount of time, that although you were sleeping less, you woke up at the *correct* time. There are these things called sleep cycles which last 1 1/2 hours at a time. If you wake up after a sleep cycle you feel less groggy and more likely to feel well rested.

If you sleep more, provided you wake up in the middle of a sleep cycle, you tend to feel unrested and tired. This is the explanation for why people feel awful just sleeping an extra 15 minutes after waking up feeling great.