morning HR issues, help!

I have been doing cardio for a while and usually get comfortable in the 135-145 BPS range. The past week I have been walking up and down my rate at a fast pace and my HR is always between 170-190 BPS even though I am breathing fine. What is up? I was told my an ex NFL player that as long as you are breathing at a 2-3 rate you are fine for fat burning. 2 seconds breathing in and 3 seconds exhaling. Should I intentionaly slow my cardio down to get back down to the 70-80 %? I am 6 foot, 180, 14 % BF and I am 31 but have been doing cardio for about 6 months 5-9 times a week.

has fat burning been effective at this accelarted rate is the question.... u been drinking redbull or having stress. ... there are alot of things that could make ur BPS raise.... even down to the weather i believe