I'll start off in this new category.

I've been a teacher for almost 10 years and an EMT (emergency medical technician) for 2 1/2 years. I can tell you that being heavier certainly has an impact on my performance.

I get tired SO much easier.
As a teacher I feel the need to sit down a lot more than I used to b/c I get worn out. Not having air conditioning in our building is also killer!

I sweat like a pig. My back kills me and I have frequent headaches. I used to be able to take a lot more noise than I used to.
As an EMT, I find that my back hurts more now picking up patients in the stretcher than before. I also sweat more than usual in my jumpsuits.
I can't wait to lose weight!