When I work with new instructors each weekend, many of them comment on how they are timid about speaking into the mic and riding. My answer to them is that it's OK to have hard breath. It means you're working, and many students like to see their instructors work. Your exertion level is a big part of creating an energy-filled workout environment. If you have met me before, you know I'm not a fan of getting off the bike (other than rider emergencies) because students lose their connection with you. Your energy input is a big part of class. That old saying (started the first MI coordinator) "you're there to coach, not get your workout" is not really correct. I agree you're not there to focus completely on yourself, but you are there to demonstrate form, resistance use, proper cadence, rhythm, alignment......etc. Walking around and talking to people doesn't quite give you the opportunities to demonstrate these critical aspects of Spinning in a meaningful way. It usually means you are talking too much and contributing too little to the collective efforts of the class participants.