Do you use a heart rate monitor during your workouts and do you trust the calories burned info it provides? I have a Polar RS300x, about which I have read good reviews as far as accuracy. I typically do 1.5 hour workout comprised of weight training and 10-15 minutes on a rope climbing simulator for my cardio. As my name suggests I'm a paraplegic so leg work is not part of my routine.
Four weeks ago I was getting readings in the mid 1200's.Today was my first workout day in two weeks and it says 1640 for today. These readings have always seemed high to me but I'm looking for opinions. I should note that I leave the monitor running for an hour after my workout. I do this not as a cheat but to monitor the post workout benefits.
Seeing as you can't add your weight, height, age, gender, and body composition into watches, I think the short answer is "not entirely". It's a ball park figure that tends to over estimate, so take it with a grain of salt. I remember my couch telling us to assume that there is 10% error in calorie readings (20-50% for treadmills, elliptical etc).
Also, I have a heart condition so my resting heart rate is faster than your average person, so I don't know if I didn't program those watches right, but mine always seemed like it waaay overestimated for me. That is another thing that might be a confounding variable for some people.
No, those things are just pure guesses. I'd trust the ones on the machines (Elipticals, Rowers, etc) more because they measure the work done and then account for the (average) efficiency of the human body of turning food into work (i.e., they usually multiply by 8). But those heart-rate monitors only are counting your heart rate and somehow turning that into calories burnt? I put no faith in that number.
This in no way answers the question, but I found this online and it looks pretty detailed and takes in to account your whole day.
A lot of the polar watches now allow you to input age, height, weight, gender etc - which makes them more accurate. not sure they do one that accounts for you % lean muscle mass though - this would add to the accuracy of the readings a great deal.
I have a garmin GPS plus Heart Rate Monitor. You input your age, height, weight, and V02 Max into the watch, and it is supposed to have a very accurate calorie measure. So I put it to the test:
Calories by Distance and Duration http://postimage.org/image/o9w5f5vq9. As you can see the calories and distance are almost a perfect match (r2 = .98). Calories by Intensity and Max Heart Rate http://postimage.org/image/imzshot7l. While more of the Track workouts (or HIIT) are on the upper level of max heart rate, there is no correlation to calorie burn. This is based on 305's calculation, not actual calories -- i.e. the advanced calorie calculation is essentially just a measure of distance.
the polars are pretty accurate for steady state cardio... not HIIT or weight training as those are anaerobic and our calories burned are different than when having an elevated HR in an aerobic state.
you can put in your resting hr, bodyfat, vo2max, gender, age, weight, height... i think even more than that too.
the HRM will be WAY more accurate than a machine at the gym- the elliptical that tells me i burned 300 calories in 30 minutes when i didn't sweat... haha, my HRM says more like 120 which sounds correct seeing i didn't work as hard as i do on the stepmill.
also the polars or any brand with the chest strap will be a lot more accurate than the kind that just goes on your wrist.
I didn't look up your model of HRM (because I am lazy), but I think my Polar FT4 or 7 (can't remember) is extremely accurate. The watch does have inputs for age, height, and weight. It is important to have one with a chest strap for the best accuracy. If you have a chest strap, it is possible that your battery is low. I have gotten extreme readings when my battery was low before. Replaced the battery and no issues :-)