Sweating it all out?
Yes you are, including all your electrolytes and mineral salts that are massively important for energy production and avoiding dehydration and fatigue.
Get these electrolytes back in after a sweaty workout by eating a banana or drinking some coconut water (my fave). A bit more hardcore would be something like a dioralyte.
You would be surprised how many people feel fatigued after a hot workout due to an electrolyte imbalance, but think it’s the workout. Don’t let it be you!