Ok, perhaps this can turn into some good future info for someone, maybe be added to a sticky thread, but I have been doing some reading. Ok, a lot of reading, on heart rate (HR) and weight loss (WL) and here is what I have learned.
I should also preface, for clarification sake, this is all being done while on a low-carb, high protein, high veggie diet. I try to limit myself to 1700 calories a day while watching things like my sugar and salt intake.
Feel free to correct me if I am wrong, but at the same time I am a bit lost, question is below.
What I have been reading is that you need to figure out your Max HR (MHR), which is generally 220- age for males, although I found another method and now can no longer find it but the age method puts me at 191, the other method gave me 187.
So with HR and WL I have been reading some semi-conflicting info.
1) Some people suggest that you work at a 60-70% of MHR to be in a WL zone because otherwise you will be in an anaerobic state which means your muscles and body will convert glucose (sugars and carbs) into fuel and therefore reducing the need to use ATPs (the energy "currency") which is what your mitochondria use to produce energy on the cellular level and is/can be derived from fats stored in your body. This is where your body burns more FAT CALORIES (so stored fat) versus just calories.
2) Other suggest you workout at an 80-90% of MHR which puts you into an anaerobic state meaning your body will use glucose more readily because it is converted quicker into fuel, and usually more readily available. This also puts you near or above most persons lactic thresholds (LH) which means your muscles are working with less oxygen then they are used to. This is where your body just flat out burns more calories but usually isn't burning more fat calories.
3) And the final area seems to be where you participate in high intensity interval training (HIIT) and that seems to "blend" the 2 different styles above into one. You push yourself for short periods, and then recovery, and then repeat for a short period of time. This pushes the muscles to work in the anaerobic state and then the recovery, and subsequent time after working out, has your body using more oxygen and therefore using more energy as it recovers.
I ask all this because that is a rather large variance in HR when trying to burn fat. Obviously I want to make sure I am doing things correctly, but what have you all found to be effective? If I am reading correctly, the lower spectrum is the easiest and least fatiguing of the WL styles, 50-70% MHR would put me around 113-130 BPM, whereas the other would put me much higher and in an anaerobic state. If it is the lower end that is most effective I now know I need to slow down on my long rides, but I also don't want to take 5 hours to go 20 miles .
After all this reading my guess is that HIIT would be the most effective way. Curious to know what others have experienced.
Some sources of my learning:
Long-ish article on HR, target HR, and WL
Shorter article tailored to cyclists and training with a HRM
General info on HIIT
Research done at some point to compare HIIT to regular cardio training (I think someone else referenced this on here when I did some searching)