system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are my abs more defined after a shower?
gpt
Your body will be more dehydrated after a long shower or bath.

You're in a hot and extremely humid environment. Your body's natural response is to sweat. However, you don't feel the sweating because it's constantly getting washed away.

In addition, the heat from the shower increases blood flow which can cause your muscles to slightly swell.