Can you wear the series four to hot yoga?

I did. There is no direct answer about hot yoga.

Perhaps not, but it does tell you what the operating temperature range is for the watch:

Apple Watch is designed to work best in ambient temperatures between 32° to 95° F (0° and 35° C)

With that information, you should be able to figure it out. Is it hotter than 95 degrees in the room while you're doing hot yoga? If so, you shouldn't use the watch.

Hey Apple... Can you please answer this question.... The watch is "waterproof" but im wondering if the heat will effect the device...

Please help, I'm really wanting to wear this to my yoga classes to get a good read on my fitness tracking

Hey Apple... Can you please answer this question.... The watch is "waterproof" but im wondering if the heat will effect the device...

Please help, I'm really wanting to wear this to my yoga classes to get a good read on my fitness tracking

Did you look at the link in the post immediately above yours?

I did. There is no direct answer about hot yoga.