Wearables and fitness trackers have become an indispensable tool to help people monitor how many calories they are burning and how much they are moving during the day. However, those with obesity are known to exhibit differences in walking speed, gait, and energy burned. Recent research suggests that fitness trackers are failing people with obesity by underestimating how much energy they are burning, which can lead to discouraging results and misguided health data.
Bridging a critical gap in fitness tracker technology
Looking for a solution to this inaccuracy in fitness trackers, scientists at Northwestern University have reported developing a new algorithm that enables smartwatches to be more accurate at monitoring the calories burned by those with obesity during various physical activities. The “open-source, dominant-wrist algorithm” is reported to be “specifically tuned for those with obesity”. It is “transparent, rigorously testable, and ready for other researchers to build upon”; the next step is deploying an activity-monitoring app later this year that will be available for both iOS and Android use.
“People with obesity could gain major health insights from activity trackers, but most current devices miss the mark,” said Nabil Alshurafa, associate professor of behavioral medicine at Northwestern University Feinberg School of Medicine.
Alshurafa explains that current activity monitor algorithms in fitness trackers are built for those without obesity, and hip-worn trackers often misread energy burn due to gait changes as well as device tilt among those with higher body weight. Wrist-worn fitness trackers provide better comfort and adherence across various body types, but they have not been rigorously tested or calibrated for those with obesity.
“Without a validated algorithm for wrist devices, we’re still in the dark about exactly how much activity and energy people with obesity really get each day — slowing our ability to tailor interventions and improve health outcomes,” said Alshurafa.
According to the report published in Nature Scientific Reports, the researchers tested this new algorithm against 11 state-of-the-art algorithms designed by researchers using research-grade devices and used wearable cameras to catch every moment when wrist sensors missed the mark on calorie burn.
Using data from the commercial fitness trackers, this new model can estimate how much energy someone with obesity is using every minute with over 96% accuracy in real-world settings, making it easier for those with obesity to track their daily activity and energy use.
Measuring energy burn
To measure energy burn in this study, one group of participants wore fitness trackers and a metabolic cart to measure their volume of oxygen inhaled and the volume of carbon dioxide exhaled to calculate their energy burn (in kilocalories/kCals) during a set of physical activities (often challenging participants to do as many activities as they could in under 5 minutes) during each task and resting metabolic rate. Another group wore fitness trackers and body cameras while living normal daily lives to confirm if and when the algorithm over- or underestimated.
“Many couldn’t drop to the floor, but each one crushed wall push-ups, their arms shaking with effort,” he said, “We celebrate ‘standard’ workouts as the ultimate test, but those standards leave out so many people. These experiences showed me we must rethink how gyms, trackers, and exercise programs measure success — so no one’s hard work goes unseen.”
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This article was created at the WHN News Desk.
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