I have a heart rate monitor that I use at every workout. A few months ago, my HR was in the high 160s-low 180s when I was doing cardio. But last night I was working out and it wasn't going above about 163, and averaged in the high 150s.

To give some background--I use the elliptical, and use either the fat burning (gradually reaches a high intensity and then stays there most of the workout, then gradually goes back down), the interval, or the cross training (longer intervals) settings. My legs are working really hard and I am feeling it in the muscles when I do the cardio, but yet my heart rate is so low. And I've tried doing less resistance and just going faster, but then my HR is between about 150 and 155.

What am I doing wrong? Should I just stay at that heart rate and be happy that I am burning more fat calories, or should I be trying to get back into that higher range to burn more calories overall? I guess I'm just frustrated at how much longer it takes me to burn the same amount of calories now as I did before. Whereas I used to burn about 12 calories a minute, now I'm down to less than 10. Thanks for the help.

Don't be frustrated... CELEBRATE!!!! It's a measure that 1) you weigh less and therefore expend less energy and 2) that your heart is becoming more efficient. Make sure that your HR monitor has accurate information... that you've updated your current weight.

I also saw a drop in calories burned over time. I distinctly remember burnig 560 in one Jazzercise class. Now breaking 500 is SUPER good. Typical is more around the 400 range.

The higher the resistance the harder your heart works, therefore a higher heartrate. When you spin at low resistance on the ellipitical you are using your legs more your heart less. You might try to mix up different types of machines or do a class once in a while. Be sure to interval your heart rate durning your cardio work outs (fast, slow, fast, slow)..When I work out my base is in the 160's and I boost it into the 180's then back down to the 160's...that is how I interval. Now I am training for a 1/2 marathon and for long runs I keep it in the 150's so I can last the two and a half hours. If you can hold 150 for an hour you are in pretty good shape.

You DO NOT burn more calories at a lower heartrate. The fat burning zone is a myth started in the 70's. The companies that make the machines use it as a selling ploy..you burn more calories by intervaling your heart rate for 30 minutes, then you do holding a lower rate for 60 minutes. Work out smart.

LesterLou-
You're right, I should be celebrating. I always keep my monitor updated within a few pounds, so it's not like I changed the weight one day and suddenly the calories dropped a bunch. I'm still a good bit above my ultimate goal, but I just went to a Kickboxing/Sculpt class and burned about 550 calories. We'll see what happens when I get down closer to goal.

Jackal-
I must have mistyped-I meant to say that I am burning more calories of fat at a lower HR. Is that still incorrect? I do try to keep my workouts quite varied, taking several different classes and also having Personal Training, during which he's always mixing up my workout. I guess the most difficult thing for me to mix up is my cardio. I don't want to run on the treadmill because I'm just afraid to mess up my knees. The most I do is switch the type of elliptical machine I use or switch the setting, but as I said I only use three different settings.

Thank you both so much for the responses. I'm trying to learn as much as I can about exercise in order to do it most efficiently and to get in the best shape possible, so your wisdom is much appreciated.

I have posted a thread on the myth of the Fat burning mode.

http://www.jennycraig.com/forum/index.php?showtopic=62006687

Talk to your trainer about interval training and how the body burns calories, I am sure he/she will explain how this works. There is so much to training and weight loss that it would be hard to explain it all to you here. You burn fat and glycogens during exercise, it's about how many calories you burn. Read the article and ask your trainer about it. I work at a gym and know that the cardio machines and heart rate monitors over estimate calories burned, beside the human body is complex and it would be really hard to determine fat burned without a V02 test and having hydrostatic testing done to see how much body fat you are actually losing. My clients are tested for body fat at least every month to ensure they are not losing lean body tissue, just because you lose weight dose not mean that you lose fat, you could be losing muscle, muscle is your fat burning motabolism. Building muscle on reduced calories is another issue along with the rest that is needed

Good Luck to you.

Thanks for the reply. I'll ask my trainer to measure my body fat, but I'm not sure if he has that little pincher thing you use to measure that (I train at the gym affiliated with my law school, and don't know what resources they have).

On another note: I am very interested in getting as fit as possible. My eventual goal is to look like one of those fitness models-not too buff, but toned. Would you recommend I take some sort of physical training class to help me get there? Or is there any online resource that I can look at?

Yes, I would too! You are already toned, you need to shed the layers of fat that we women have. Those thin models don't eat very much, and they dehydrate and starve themselves before a photo shoot.

You need to work on losing body fat, continue what you are doing, lose the weight in a healthly way, so you will keep it off for life. Maintaining is the hard part! Educate yourself, there are thousands of books out there, use your common sense, if it sounds to good to be true, take a second look at it. Get yourself a trainer who has good creditials, one that can teach you about weight loss, and give you a well balanced workout. You can get yourself certified, it is costly..and most cannot make a living at it.

Losing weight is all about the food, you can be fat and fit. This is the first things that I tell me clients, 76% food, the rest is exercise, and maintaining your muscle mass. I also try to get my clients involved in a physical activity, cycling, swimming, hiking join some sort of club where you have fun keeping active, make it a part of your social life.

Keep at it and make it a part of your life, not your life, I see too many women burn themselves out.

Good luck! Jackal

I just brought new digital Polar F6 Heart Rate Monitor, Pink Coral it really works well.