system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 what's the purpose of sodium or salt in our sweat? I understand sweating is supposed to cool us down but why is there salt in sweat.
gpt
Your body functions best when it maintains the right balance of salt and water. This is why hospitals hydrate people with saline solution instead of pure filtered water. Add too much water without a comparable amount of salt and it throws off the balance.

*Extract* too much water without a comparable amount of salt and it also throws off the balance. If your sweat didn’t contain salt, then by sweating you would be concentrating the salt in your body, which ultimately wouldn’t be very good for you.