When I first began wearing a heart rate monitor/calorie counter I wore the Polar brand with the strap around the chest to measure the heart rate and the watch on the arm which worked along with the strap. I loved seeing my heart rate climb and the calories add up during a spinning class! Recently, I have been wearing a Sportsline brand that is the wristwatch type only - no strap required. Therefore, I basically wear it ALL the time like a normal watch. (I can track calories burned throughout the entire day). I had been told that this device was much more accurate than the calorie counters found in exercise machines. The following is what my research brought to light.
First of all, I will address the calorie calculators found in most exercise equipment found in gyms. ABC15.com presented an article on this subject where they put the machines to the test. They put an investigator, Joe Ducey, through a V02 test (which is the most accurate test known for measuring exactly how many calories are burned doing an activity.) They had him perform a ten minute walk on a treadmill. Using the V02 measure he burned 60 calories. He then walked on the treadmill for 10 minutes using the treadmill's calorie counter. It showed he burned 57 calories. The difference was only 3 calories - or five percent difference. I can live with that difference! That being said, you do have to keep in mind that the gym equipment is programmed with a textbook equation and "we all differ how we metabolize calories when we're doing exercise."
The same investigator performed the tests on a Stairmaster machine and stationary bike. Both machines underestimated the amount of calories burned. I personally found this interesting as I have always assumed that the machines would OVER estimate the amount of calories burned. Either way, I think the exerciser needs to realize the number is a ballpark figure as each person is different and exercises differently.
"Treadmills, ellipticals, stationary cycles and similar units display two metrics. . . . The displays of heart rate, speed and distance are straightforward and fairly accurate. . . But the calorie counter is crafted to reflect the burn of an average exerciser, not you in particular, and thus it could be off by a bit." The Washington Post; Lies, Damn Lies and Calorie Counters.
Now, as far as personal calorie counters, I use a Sportline heart rate monitor that has touch sensors on the watch face. Others may have a wireless chest transmtter. This particular company has various devices ranging from $60 - $120. Just as with the machines, the calorie counters give a rough estimate of the number of calories you burn during a workout. Some can have a margin of error of 20%. There are so many variables that are considered in determining the amount of calories burned for each individual. Many factors affect your caloric expenditure, and a pedometer or heart rate monitor cannot calculate some of these factors, such as body composition or metabolism rate.
An article in www.livestrong.com on this subject states, the "more personal information you input into the device, such as your weight, age and gender, the more accurate the calorie information will be. Even if the numbers aren't exact, you can use them in relation to each other. You burn 200 calories in Monday's workout and only 150 calories in Wednesday's workout. If the length and style of the workouts were the same, you did not work as intensely on Wednesday." I say that does make sense. I think other considerations are how you feel on that given day, how much sleep you had, what you had to eat the evening before or the hour before your workout. Lots of things can contribute to varying numbers, but, all in all, I think the ballpark range is great information to have. I don't want my day (or anyone else's) to revolve around calories! If you ARE trying to drop a few pounds, though, this knowledge is helpful, as we all know it comes down to calories in versus calories out! The types of personal devices that contain heart rate monitors are also helpful in making sure you are actually working hard enough to get your heart rate up, and also make sure you are not overdoing it by allowing it to get too high.
So, long story short, it seems that the calorie counters are reliable enough. They are a great tool for looking at one workout in relation to another and are a reminder to make us work just a little harder at times!
Do you wear a calorie counter? What do you think about the numbers?