If you look around, it looks as though everyone has some sort of techy watch around their wrist.
Apple watches, Fitbits, Whoop, and the list goes on.
Many people wear these not just to see what time it is, but to see how many calories they’ve burned throughout their day or their workout.
But just how accurate are they?
TLDR; they’re not great.
Pretty much any device that tells you how many calories you’ve burned during a workout is simply not even close to the truth.
These devices might be great at tracking certain things like step count and heart rate, but a recent paper basically solidified that they suck at estimating how many calories you’ve burned.1
Researchers at Stanford looked at 7 popular devices and put some people through some workouts to see how accurate these devices really were.
To sum it up, even the best device came out to be off by 27%!
The worst? Off by 93%.
Meaning, if a tracker says you burned 1000 calories during a workout, you probably only burned a few hundred.
Now, this paper came out in 2017. And, sure, the technology has gotten better since then.
But it’s not the technology that is the problem.
These trackers may ask for your age, height, sex, and general activity level, but there are SOOOO many more factors that play a role in how many calories you burn.
Training modality, muscle mass,muscle fibre type, exercise selection, hydration levels, body temperature, room temperature, altitude, meal timing, hormones, caffeine intake, medications, thyroid function, sleep duration, genetics, etc etc.
That list could go on and on …
But ok, that’s for wearable devices. What about the calorie counters on treadmills and other exercise machines?
Well, they’re also not great tbh.
One paper reported that treadmills are off by about 20%, while another paper reported that ellipticals overestimated by approximately 100 calories for every 30 minutes of exercise.2,3
What If I'm Trying to Lose Weight?
At the end of the day, the number on the screen of these devices don’t really matter …
The amount of calories you burn during a workout are >5% of the amount of calories you burn throughout an entire week.
So if your goal is to lose weight, you shouldn’t rely on burning calories during workouts to put you in a deficit.
It can help, of course.
But look at it this way, you maybe spend a few hours a week exercising. Meanwhile, there are 168 hours in a week. So relying on burning as many calories you can during a 45 minute workout is miniscule compared to the time spent doing other things.
Instead, paying attention to your calories intake (aka, what you put in your mouth), and comparing it to how the scale moves over time is a better way to try to lose weight.
The Good
Don’t throw out your Apple Watch yet. There are some good things about these gadgets too.
One good thing about these trackers, though, is that they can serve as a motivation tool for some people.
Some people like to use it to compare from workout to workout. So if normally their trackers say they’ve burned 200 calories by the 1 hour mark, but their next workout says they’ve only burned 100 calories by that time, that could mean they need to boost their intensity a bit.
Same can be said if you track day-to-day calorie expenditure. If your tracker says the average number of calories burned is about 1000 a day, but then you have a day where it says you only burned 700, it could be a sign you were a lot less active than normal. For some, that would give them the boost they need to go for a walk, hit the gym, or to crank out a few squats during a commercial break.
Although these devices may not track calories perfectly, they still have other metrics and tools that can be handy.
They can help log workouts, help keep you accountable, and help motivate you to exercise.
A lot of people keep track of their daily movement through closing their rings or hitting their step count. These devices can make it easy to keep track of these things.
Who doesn’t feel pumped when they’ve got a new workout outfit on and some tech to go with it?
This idea, often called “enclothed cognition,” is when what you wear influences your mindset.
By putting on some fancy tech you can be motivated to go workout, and maybe even stay a bit more consistent with your workouts. Some of them even let you keep track of your progress over time (which can help motivate you more).
All in all, just know that while they might not be great at tracking how many calories you’ve burned, they can still be handy in other ways - and quite stylish too.
Final Thoughts
Our goal at Delta Kinesiology is to help women reach their health and fitness goals, whether it be online, in the gym, or in-house! We specialise in conditions and injuries that women are more likely to experience, and we tailor the sessions using evidence-based principles and methods to help you reach your goals. Whether that be going about your day pain-free, building muscle, improving stamina, or feeling better about yourself, we are here to help.
Check out some of the ways we can help below!
References
Shcherbina, A., Mattsson, C. M., Waggott, D., Salisbury, H., Christle, J. W., Hastie, T., Wheeler, M. T., & Ashley, E. A. (2017). Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort. Journal of personalized medicine, 7(2), 3. https://doi.org/10.3390/jpm7020003
Byrne, N. M., Hills, A. P., Hunter, G. R., Weinsier, R. L., & Schutz, Y. (2005). Metabolic equivalent: one size does not fit all. Journal of applied physiology (Bethesda, Md. : 1985), 99(3), 1112–1119. https://doi.org/10.1152/japplphysiol.00023.2004
Glave, A. P., Didier, J. J., Oden, G. L., & Wagner, M. C. (2018). Caloric expenditure estimation differences between an elliptical machine and indirect calorimetry. Exercise Medicine. https://www.exercmed.org/journal/view.php?doi=10.26644%2Fem.2018.008#:~:text=There%20are%20a%20few%20key,different%20between%20males%20and%20females.
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