Are Treadmill Calorie Counters Accurate?

My patient said he ran 20 km on a treadmill recently. He also told me stats like his average pace and treadmill incline of the run and calories burned. Since he mentioned about the calories he burned, I told him that they were not very accurate.

Different treadmill manufacturers will have their own formulas that they use for their treadmills, elliptical, X-trainer, stepper etc. Speed, treadmill incline, and distance are typically used to calculate how many calories you burned.

However, for a more accurate reading, your gender, height, weight, muscle, fat mass, heart rate and fitness levels are typically needed as well. Note that a higher heart rate may be associated with greater energy expenditure, hence a lower heart rate running at a certain pace means you are fitter and will burn less calories.

Heart rate is affected by temperature (of the gym), medication, food you ate, what muscles are being used and whether your run is continuous or in spurts/ bursts.

You may also notice that your run becomes much easier when you hold onto the hand rails while running. By taking some weight off by holding on to the rails, actual effort is reduced but the calorie counter does not account for that and will overestimate calories expended.

Treadmills and elliptical machines need to be calibrated regularly (especially in busy commercial gyms) otherwise the speed you may be running at may not be accurate. That discrepancy alone can influence the accuracy of the calorie count.

I could not find much research specifically on how accurate the calorie counts on treadmills. There was a 2018 study by Glave et al (referenced below) involving elliptical machines. Their study found that the calories burned were significantly overestimated. More than 100 calories were added for a 30 minute workout.

So take your exercise machine calorie counts with many grains of salt since they are definitely not accurate and may be way off in some cases.

You can certainly use a smart watch to track your calorie estimates too but even these tend to overestimate energy expenditure. My previous post covered that, but do note that fitness and smart watch technology is consistently improving so they may be more accurate now.

One can also use an online calorie counter to provide an estimate of how many calories you've used. Again it's just an estimate.

Remember not to totally rely on treadmill calorie counts or your smart watch to rule your workout. Sticking to your exercise plan consistently is what really counts, not just the numbers you see on the treadmill or elliptical machine.

Reference

Glave P, Didier JJ, Oden GL et al (2018). Caloric Expenditure Estimation Differences Between An Elliptical Machine And Indirect Calorimetry. Ex Med. 2:8. DOI: 10.26644/em.2018.008