system
Given the following post, respond as if you're commenting on Reddit:
human
Why does it sometimes take me an hour to fully wake up in the morning? Once my brain is active (out of its sleep cycle), what is preventing me from feeling as I do at midday? 

Even if a REM cycle is interrupted, I'm not sure why it takes so long to not feel groggy sometimes.
gpt
A lot of it has to do with your circadian rhythm in addition to cortisol lévéls. Cortisol is considéréd thé anti-sléép hormoné, and thé morning péak is approˣimatély at 8am or around 30-60 minutés aftér waking. It is éˣcitatory (a link to thé cortisol-stréss résponsé) so wé nééd it to féél that boost in thé morning. 

Thé stupid mold thing is making it annoying for mé to link, so you can do a googlé scholar séarch on cortisol and sléép for somé sourcés if you aré intéréstéd in furthér réading.