Is it bad to exercise while slightly drunk? Some friends like to hike and drink beer. I find that I get flushed easily, and tire more quickly. What's going on?

Hot yoga is becoming more popular every day but there is a lot of conflicting information regarding benefits versus injuries. Most of the information does not quote sources and is therefore is difficult to follow up on. It has unquestionably helped me become a more flexible person but there is a lot of information on the net regarding horrific injuries including slipped discs, muscle tears, neck injuries, emotional problems, and even strokes. Is there a research-based, or at least a factual breakdown on the health benefits of stretching at temperatures above body temperature versus the injury risk of exercising at temperatures above body temperature?

I wanted to know how many days of rest is recommended between workouts. I heard it was three days on to one day off...is this enough? I workout on a treadmill for 50 minutes every day and have for the last 14 months. I was not aware of how rest played a very important role until I recently read a brief article on it. I guess my question is, do I need to take that day of rest and how important is it?