Advice about Heart rate during exercise

http://exercise.about.com/od/weightloss/a/The-Truth-About-The-Fat-Burning-Zone.htm

Also what exercise and duration are those 800 calories logged against?

A couple of years ago I had some tests run (no idea what they were called) that told me my BMR and at that time I was told that I was wasting energy if my heart rate went over 151, that I was not gaining anything by it being that high so I would get more fat burning benefit to keeping it between 138 and 150, so it sounds to me like he is right on.

http://exercise.about.com/od/weightloss/a/The-Truth-About-The-Fat-Burning-Zone.htm

Article is true. There is a more benefiical zone for fat burn but weight loss is all calories burned. Why not do anaerobic for weight loss? IME as you stop your heart rate gets slower and slower but never to resting heart rate so you will also burn calories in the fat burning zone while chillen recovering from the intense workout.

I'm curious as well. I'm a 40 yr old male. I am currently following the Body-for-Life diet and exercise plan. I run 2-3 days per week on the treadmill and resistance train 3 days per week. I run in the morning in a fasted state and eat an hour after my run. In theory, your body is feasting on your fat to replenish the energy consumed during the exercise and after. I am down ~12 lbs in the past 6 weeks, which I've read is pretty much on the mark @ 2-3 lbs per week, which is the rate (again, in theory) that a body can safely burn fat. This doesn't account for any lean muscle I am gaining.

I run intervals for 20 minutes from 5.5 MPH to 8 MPH ( I average 2 miles in 20 minutes) and my heart rate after warm up stays in the 150-175 BPM range. I like that I get a good sweat going and keeping my heart rate lower than 150 doesn't seem like a very good physical challenge, which would probably lead to boredom. If that range truly doesn't burn fat then where is my fat going? My love handles are dissolving and when they are gone I think whats left of my belly will follow.

I think there are several levels of confusion here. The first is, if you are lifting, you should be lifting for strength, health benefits of it and long term calorie burns while not lifting, not with the express target of heart rate at optimal for weight loss. If you target fat burning specifically, then a lower heart rate is more efficient for it, yes. However, generally that should not be the purpose of lifting. Lifting doesn't burn all that many calories in an of itself while you are doing it, especially if you aren't very strong. The main benefits of lifting are burning calories throughout the day with the increased muscle mass and increased metabolism that build from you doing the sessions. To lift for an aerobic goal is more circuit training, and if that is your target, its a completely different animal, yes you should look at heart rate then, however keeping a low fat burning hr on circuit training is also not really optimal either: you want short bursts of intense effort, not long slow even effort that is optimal for fat burning during the exercise.

Next, a target heart rate really depends on what your resting heart rate is, what is your max heart rate, and how easily it takes to get into the range you stated, what conditions you have, and what you are trying to do. Someone starting at a high heart rate may not take that much of an aggressive load to get to into that 170 range, whereas someone who's heart rate is low, that would be a massive load, say sprinting, to get to 170 bpm. Probably, your doctor knows more details than random people online however, he may know other facts about your health condition or body condition, so if it is a warning because of a condition, not purely based on a fat burning heart rate, listen to him.

Really in general you should do both kinds of exercise, aerobic 150+min/wk and lifting/anaerobic for best results, keep an even targeted lower heart rate during the aerobic exercise for fat loss if you wish, and lift for the health benefits and long term calorie burn. If you are lifting, in general, unless you have a health condition you have to worry about, or are getting faint, etc, heart rate shouldn't even be on your mind during a lifting session, its irrelevant to the main goals of lifting. HR will go up and down all over the place dependent on the actual weight and effort and unless you have a health condition, or are exercising so intensely that your body cant handle it, or lifting so light its not much effort for you, the heart rate isn't a focus at all for a lifting session. This is also why HRMs generally are bad for tracking lifting burns.

I almost forgot the most important fact here for one of your questions, you did not mention how long you lift, but I'm going to guess an hour, and if so, you are burning much, much less than half the calories you are logging. I am larger, taller, male and much stronger than you (all factors that increase calorie burn), and I log around 300 calories for an hour of lifting. I don't know how strong you are exactly, no, but I'm pretty certain you arent doing 300lb bench presses, 900lb leg presses, 420lb rows are you? Whatever you do, even if you are close, just take the fraction of that weight and divide your calorie burn by it and its more realistic: Say you do 100lb bench presses, well thats 1/3 what I do, so 1/3*your 800 burn is more like 266 cals. Even that rate is probably high for you. You can see if you log 800 cals, eat back half (400), you have given yourself a SURPLUS of calories, and this explains your weight gain.