Not Losing Weight As Fast? This Could Be Why!

I use a site to calculate my calorie burn based on average heart rate. When I use a machine to work out, I both observe the machine's output vs my own calculation of my HR. I take that number, and time, and put it into a site's input boxes, and it outputs my gross calorie burn.

But what I just learned about Gross and Net calorie burn was interesting, and for some of you folks that do light workouts....you might not be getting the burn that you think.

Here is what I learned:

Gross calorie burn is how much calories you burned TOTAL in that given time span. I worked out for 25 minutes, my average heart rate was 155 bpm, so I burned a total of 385 calories.

Net calorie burn is how much calories you burned MINUS the calories that you WOULD have burned had you done nothing. In other words, your Resting Metabolic Heart Rate is a specific amount. For me, it is about 100-120 calories per hour. If I do nothing all day, and just lay in my bed and watch movies all day, I will burn 2400-2880 calories on any given day.

To measure Net Calorie Burn, you take that number that you see on the machine, or on your app, or on MFP (that number you see when you put in the minutes worked out), and you subtract it by the amount of calories you were already going to burn in that time frame. In my case:

I burn 100 calories per hour doing nothing.
I worked out for 25 minutes, so I would have burned 41 calories in that time had I done nothing
I burned a gross 385 calories on the machine
Therefore:
385 - 41 = 344 net calories burned

If you log workouts, this is the number you should be inputting. The significance is greater for those who do lighter workouts and don't raise their heart rates for an extended period of time. What you would have done is a constant, whereas what you did is variable. So If I burn 1000 calories in an hour, I know that I must subtract 100 from that total, so I really worked out for 900 calories. That is a 10% miscalculation if I put in 1000 calories burned. But if someone burns 300 calories in 1 hour and logs 300 calories, that is 30% of their workout they are miscalcuating. If that someone is only looking to lose 1/2 pound a week, you are hindering your progress by almost 50%!

It is a greater difference factor for heavier set people too because their heart rate is already beating higher and their ability to sustain a high heart rate is more difficult than the averagely healthy person, so the resting metabolic heart rate also plays a part.

You can get all the information here:
Knowledge: http://www.shapesense.com/fitness-exercise/articles/net-versus-gross-calorie-burn.aspx
HR based Calculator: http://www.shapesense.com/fitness-exercise/calculators/heart-rate-based-calorie-burn-calculator.aspx