Professional Track » Overall, the wearables seem to be underestimating calorie burn

Overall, the wearables seem to be underestimating calorie burn

Your Fitbit is lying to you

We used to wonder how accurate the calorie count on treadmills and ellipticals was. (The answer: not very.) Now we have more sophisticated devices that cheap canada goose uk track our every move, canada goose outlet reviews but the question is still the same: Canada Goose Jackets How much can we trust the numbers?

Researchers at Japan’s cheap Canada Goose National Institute of Health and Nutrition recently ran an impressively detailed study to compare 12 different wearable devices, including the Fitbit Flex, Jawbone UP24, Misfit Shine, Garmin Vivofit and Withings Pulse O2, to two widely accepted methods of estimating calorie burn. The results, canada goose outlet published in the cheap canada goose May issue of JAMA Internal Medicine, offer some interesting insights.

The best part of this experiment, from my perspective, is that the 19 volunteers in the study wore all 12 wearables at the same time. There’s a picture in the article of what that Canada Goose Parka looked like, canada goose outlet online which is pretty hilarious. There were six wrist bands, four waist mounted devices and two pocket devices.

One part of the experiment involved spending 24 hours in a metabolic chamber, following a standardized protocol including “3 canada goose outlet parka meals, deskwork, watching TV, housework, treadmill walking, and sleeping” while their canada goose outlet store caloric expenditure was measured by carefully monitoring the chamber’s temperature, gas composition and so on.

On average, the subjects burned 2,093 canada goose outlet jackets calories during canada goose black friday sale this 24 hour period. Here’s how far the various wearables deviated from that value:

Image courtesy of JAMA Internal Medicine

There are consistent differences in the devices. For example, the Jawbone and Garmin devices underestimated calorie burn by a couple hundred calories on average, while canada goose clearance the Fitbit and Misfit both overestimated.

The second part of the experiment took the subjects out of the lab and into the field. The subjects drank “doubly labeled water,” which contains rare isotopes of both hydrogen and water; calorie burn can be estimated by tracking how long it takes for those isotope to appear in your urine.

The subjects then canada goose outlet nyc spent the next 15 days living their normal lives while wearing all goose outlet canada 12 devices at all times and collecting their urine for later analysis. They were allowed to take the devices off “when bathing, special activities in which wearing the devices would be canada goose outlet toronto factory difficult, or when charging the battery.”

Over those 15 days, the subjects burned an average of 2,314 calories per day, according to the doubly labeled canada goose outlet canada water. Here’s how the wearables stacked up, in the same order as the previous graph:

Image courtesy of JAMA Internal Medicine

Again, the official canada goose outlet Jawbone and Garmin produce lower values than the Fitbit and Misfit, so that seems like a consistent finding. Overall, the wearables seem to be underestimating calorie burn this time but that’s not surprising, since it’s far more likely that over a 15 day period you’d have canada goose store a greater amount of time with the devices off for charging, sleeping, and those other “special activities.”

The conclusion of the study is that “the findings presented herein suggest that most wearable devices do not produce a buy canada goose jacket cheap valid measure of total energy expenditure.” From a research perspective, where you need to know the actual number of calories being burned, that may be true.

But for real world use, where the most important thing is getting consistent relative results so canada goose uk black friday you can tell whether you’re burning more or fewer calories compared to a previous day, the results actually seem pretty decent.

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