We received this question from one of our readers:

So today I have been on the Elliptical machine for 30 minutes and according to the machine, I burnt 310 calories. According to my HRM, I burnt 384 calories.

Which one is the most accurate?

Is the HRM alone more accurate because it takes into account sitting Heart Rate?

Is the Heart Rate Monitor with the HRM ready cardio machine more accurate because it takes into account your Heart Rate plus actual speeds and levels worked?

Working out on LifeStride Ellipticals.

Good question. I’m assuming your goal is weight loss, since you’re counting calories, so I’ll answer the question from a weight loss perspective.

The difference between the two different readings you have is 74 calories, about as much as one of those little yogurts that are supposedly great for weight loss (they’re not). The difference is pretty much negligible and here’s why:

Let’s say you’re burning 350 calories in a workout like this and let’s assume you need to burn 3500 calories to lose 1 pound of fat. It would take you ten workouts like this to burn 1 pound of fat, all other things being equal. If you use the numbers you provided, it would take you about 11 and 9 workouts to burn 3500 calories for the 310 and 384 calorie workouts, respectively.

“But Matt, that’s not negligible at all! I’d need to do 2 extra workouts to lose 1 pound of fat!”

True, but you must keep in mind that those 74 calories can be blasted by a few extra nuts, one more bite of steak, a tablespoon more cream in your coffee… you get the idea. The amount of calories you burn during exercise is not something that is worth focusing on as an absolute measurement. However, I do feel that if you pick one method of measurement and use that as a tool of progress, it may be productive. In other words, if you choose the HRM and you burned 384 today, try to burn 400 tomorrow, and 415 the day after, and so on, regardless of what the absolute number is.

Overall, I think the HRM compatible machine will probably give you a more accurate number, but caloric estimations are not all that accurate even in tightly controlled settings. It’s a great question and sometimes these number games are fun to focus on because they increase motivation. Unfortunately, the calories in/calories out equation is so complex, I don’t feel a 74 calorie difference is worth sweating over. Remember, exercise to maintain muscle while dieting and then to reap the overall health benefits. If weight loss is your goal, focus on counting the calories that are going in… they’re far more important.

Do I use my HR monitor or the elliptical to tell how many calories I'm burning?
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