Hot yoga entails loads of sweating. This means, as you can understand, that you’ll need to drink a lot of water when regularly practicing hot yoga. It is highly recommended to fill yourself up before and after class, but try to not drink water during class. As counter-intuitive as it may seem, the less water you drink during class, the easier it will get. This is because it takes a little while for the body to fully absorb the water you put into it, so the water you do drink will lay heavily on your stomach a big part of the class.
So how much water will I need to start drinking? Well, the common suggestion from most doctors is about 8 glasses a day(a bit of an unclear amount, but okay). I recommend getting at least 3 liters of water each day. If this seems like a lot, that’s because it is, but you’re gonna need it. At the same time, try to not have too much water in you right before class. A good rule of thumb is to fill up most of your water need up until around 30 minutes before class, and then have little sips right before if you feel like you need it. You won’t want to need to go to the bathroom either once the class has started, that’s very annoying.
Of course, as you go along your hot yoga practice you will learn what works best for you. I do recommend you view this as a guideline, and not a rule. And by all means, make mistakes, it’s how you learn.