It’s a dirty word nowadays (salt, that is) but if you’re sweating a lot and feeling very tired, it might help.
When we lived in the Middle East, everyone but children took salt tablets during the extremely hot and humid months - dispensers were provided by the company.
I remembered this a few years ago when we were on hols in Darwin, N Oz, during a hot and very humid season. I was virtually wringing my hair out after 10 minutes out of doors. There was a lot or urging to drink water, but nobody mentioned salt.
Feeling absolutely exhausted and wrung out (in both senses) and having remembered the salt tablets, I put extra salt on my chips at lunchtime (choice was quiche or buffalo pie with chips!) and felt miles better in the afternoon.