system
Given the following post, respond as if you're commenting on Reddit:
human
Why does strong coffee make me uncomfortably tired sometimes?
gpt
You are dehydrated. If you were properly hydrated caffeine would not make you sleepy. The more water you've drank before cup of coffee the better your body handles the restricted blood flow from shrunken blood vessels.

I'll be searching for references. This is the answer I've seen from a similar post.