Lv -- I need to ask you about the science behind your statement:

Also, if you want to burn fat - when you start your ride, ease into it and breathe through your nose exclusively for about 20 - 30 minutes, that helps burn fat as opposed to building your heart muscle.
I am not familiar with this at all, I am very familiar with proper diaphragmatic breathing during cycling. But even this is not a mechanism to burn fat, it is a mechanism to increase the volume of oxygen intake per breath (as well as to assist with bringing the heartrate down).

Maybe I misinterpreted your statement...