Are Calorie Counters Accurate?
Are calories burned/counted on a treadmill or elliptical trainer accurate?
In general, the calories burned reading on most cardiovascular equipment is not very accurate. A small computer is placed within each piece of exercise equipment. The computer exists for the purpose of calculating caloric expenditure for your workout using a standardized formula. The read-outs from cardiovascular equipment for weight-bearing aerobic exercise, such as a treadmill, is typically more accurate than the read-outs from cardiovascular equipment for non-weight-bearing aerobic exercise because the former takes your body weight into account and account for factors such as speed.
How accurate are calorie counters on exercise equipment?
Experts in this field believe that the caloric expenditure reflected on cardiovascular exercise equipment is overestimated by 10 to 15% but often disagree as to the accuracy. Research conducted at the University of California at San Francisco’s Human Performance Center, checked the accuracy (using V02 max equipment in laboratory monitored workouts) on four pieces of exercise equipment. The calorie over-estimation based upon 5 minute workouts was as follows: treadmill: 13%, stationary bicycle: 7%, stair climber: 12% and elliptical trainer: 42%. This does not completely support the ‘weight-bearing’ theory.
Do calories burned depend on heart rate?
Yes, the amount of calories you burn during exercise also depends upon your heart rate. Working closer to the top of your maximum heart rate generally burns more calories overall. There are several types of heart rate monitors that you wear during exercise, such as a calorie counter wrist watch or chest strap/ monitor. These gadgets also calculate caloric expenditure and constantly measure your heart rate, throughout your workout. These calorie counters use the Karvonen formula – 220 minus your age in years (to come up with your maximum recommended heart rate).
How accurate are heart rate monitors for calories burned during exercise?
You program these heart rate calorie monitors based upon your personal information, including your age, height, weight and other details. The monitor uses the Karvonen formula to prompt you to speed up or slow down so that you are exercising in your optimal heart rate training zone. Many experts agree that heart rate monitors for calories expended are more accurate and have a narrower margin of error than conventional exercise machine calorie counters.
Are calorie counter watches accurate? How accurate are fitness watches?
The accuracy of calorie expenditure using fitness or calorie counter watches is debatable. Based upon a research study published in 2004 in the ‘Medicine & Science in Sports & Exercise’ journal, high-quality calorie counter watches, such as the Polar S410 heart rate monitor, have a low margin of error in respect to accuracy of calorie expenditure. According to this study, the Polar S410 monitor estimated the caloric expenditure of workouts with an impressive 75% accuracy. However, according to Good Morning America technology expert Becky Worley, the caloric expenditure estimation of cardiovascular exercise equipment is more accurate than that of fitness watches. According to the results of the University of California at San Francisco’s Human Performance Center study (above) the large cardiovascular exercise machines over-estimated caloric expenditure by an average of 19%. The fitness watches, however, over-estimated calorie expenditure by a large margin of 28%.
How does a calorie counter watch work?
Calorie counter watches work in much the same way as cardiovascular exercise machine calorie counters work. They have a small computer which uses formulas to best estimate caloric expenditure based upon the exerciser’s personal details/profile. They are slightly different because they constantly measure heart rate (in addition to incorporating a person’s height, weight and gender to calculate calories burned). Unlike large exercise machines that use (mainly) distance traveled and speed, etc., to measure calories the estimation of the watches are based more upon the exertion of the exerciser. While not exact (and accuracy varies by brand/quality) in terms of calories burned, the readouts are consistent so you can uses calorie counter watches to compare the intensity of different workouts.
REFERENCES
- Tufts University John Hancock Research Center on Nutrition: Faculty: Miriam Nelson PhD.
- Crouter SE et al. Accuracy of Polar S410 Heart Rate Monitor to Estimate Energy Cost of Exercise. Medicine & Science in Sports & Exercise; 2004.
- Good Morning America: Don’t Get Burned by Calorie Counters: http://abcnews.go.com/GMA/Weekend/exercise-calorie-counters-work/story?id=9966500