As we know, millions of people use some kind of activity monitor (be it a bracelet or a smartwatch) to closely monitor exercise performance and take care of health. Often, the data generated by these devices is shared with a doctor. And the big question: is this data accurate?
Professor Euan Ashley, from Stanford University School of Medicine, did a study with 60 people (31 women and 29 men) who tested seven exercise / health monitoring devices (Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and Samsung Gear S2). All of these people used the seven devices to walk / run on treadmills and bicycles.
The heart rate of each volunteer was measured with a medical grade electrocardigraph; the metabolic rate was estimated with an instrument to measure oxygen and carbon dioxide in breathing, a good way to understand metabolism and energy expenditure. The results of the devices used, then, were compared with the measurements of these two instruments.
According to student Anna Shcherbina (who is also one of those responsible for the study), for a lay user, in a non-medical environment, it is ideal to keep the error percentage of these measures below 10%.
The good news is that, according to Ashley, heart rate measurements were much better than expected; in contrast, the energy expenditure measures were far from the mark stipulated by the study. "The magnitude of how bad they were surprised me," she added.
The big question is that it is not easy for the manufacturers of these devices to create an accurate algorithm for a wide variety of people, after all the energy expenditure is variable based on the level of fitness, height, weight, etc. This is an estimate that literally varies from user to user; Heart rate is measured directly, so there is little mystery.
To have an idea of ??what this represents in practice, of the seven devices used, six of them measured heart rate with error rates below 5% (which is great!); in the calorie burn estimate, the data presented by the devices ranged from 27% to 93% compared to the professional / medical meter (remembering that, in the ideal world, this discrepancy could be a maximum of 10%).
The good news for Apple Watch owners is that the Apple watch was the one that got the best performance, both in measuring heart rate and in estimating caloric burn. At the other extreme we have the Samsung Gear S2, which got the worst results.
Interestingly, the devices in general are better at measuring data collected during cycling than walking / running; mistakes also tend to be more common in men than in women, especially those with a higher body mass index and darker skin tone.
For those interested, the study was published in Journal of Personalized Medicine.
Apple Watch Series 2
Price view: R $ 2,699.10Installed price: in at 12x R $ 249,92Sizes: 38mm or 42mmColors: diverseRelease: September 2016