Ahhh Heart Rate Monitor Vs Cardio Machine Calories Burned

There is no set answer. Exercise machines are programmed with different algorithms. Some, like treadmills, are well established and accurate, some are not.

You cannot make a blanket statement about "machines" vs "HRMs", because within each category, there are variations. Another variable is the accuracy of the setup information one programs into an HRM (in the vast majority of people, the setup information is only a rough approximation). And lastly, you have different, non-exercise variables -- thermal stress, illness, cardiovascular drift, type of muscle movement to name a few -- that can affect heart rate and distort the HR/VO2 relationship upon which HRM calorie estimates are based.

In short, most people don't really know.

The OP is showing a picture of a Life Fitness Integrity cross trainer. That model is the newest iteration of the LF9500HRR, the first Life Fitness rear-drive cross trainer which was first sold in 2000. While there have been a number of upgrades since that time, the software and the algorithms used to estimate calories are older and have always overestimated. Other models have been introduced since that time, but this one is the most reliable, is extremely durable, and has a great price-point. Therefore, it is still the preferred model for most health clubs.

Life Fitness produced another model, the 95X cross trainer, 2004. That used a version of the old software as well. It was not well-received nor well-executed. A number of people lost their jobs over it, and they finally discontinued the model in 2008 (although it is still manufactured and sold in Europe). In trying to make the design work, they modified the movement and also upgraded the software. This time the calorie algorithms were derived from research they did in their own biomechanical lab, and were specific to the machine and the movement. I forget the software revision number, but if you find one of those, your calorie readings will be very accurate--as accurate as I have seen on any exercise machine. They are about 25%-30% less than comparable readings with the older software (on the Integrity model).

One of the biggest fallacies in fitness is the idea that an HRM is more accurate "because is knows you". People mistakenly think that HRMs are more individualized and accurate because they ask you to input more variables.

Wrong.

HRMs have to ask for more variables to try to make up for the inherent shortcomings of their methodology. They need more data inputs to attempt to improve the "fit" of the equations to the wide scatter of data received during their validation studies.
They need to play mathematical games because they do not measure anything but heart rate, and trying to fit heart rate into a calorie prediction model is like trying to stuff an agitated python into a burlap sack.

If you:

1). Have a quality-brand HRM with years of original research supporting its calorie-estimating algorithms (which knocks out most HRM brands right off the bat)

2) Have input the HRM with your ACTUAL maximum heart rate (not calculated) and your ACTUAL VO2 max, and ACTUAL resting HR, along with the other data.

3) Are performing relatively simple, steady-state aerobic exercise, and are not using ANY handrail or other support

4) Are performing relatively simple, steady-state aerobic exercise that does not involve a lot of upper-body movement or isometric movement, or higher resistance

5) Are not affected by caffeine or other stimulants, fatigue, or illness

6) Are exercising in a thermally-neutral environment with optimum temperature and humidity

7) Do not experience significant cardiovascular drift during your workout

THEN

Your HRM calorie estimate should be reasonably close--maybe within 10 or 15% of the actual number. And that also assumes that as ANY of your parameters change--weight, resting HR, VO2 max -- you update the settings on the HRM.

If any of those conditions are not met, then your HRM will be off -- maybe by a little, maybe by more than 50%-70%.

So use them for whatever value they provide, but be realistic about the numbers you are getting. And drop the idea that your HRM is somehow inherently more accurate that the machine, just because the HRM numbers are different. The HRM manufacturers want you to believe that, but they are blowing smoke up your wazoo.

And, in the overall scheme of things, a 50-100 calorie discrepancy is meaningless. It's a flicker, a blip, random chance, whatever you want to call it, but it is not significant.