Fitness Trackers Bad at Measuring Calories Burned, Study Says

Source: VOA
Date: May 26, 2017

A new study suggests fitness trackers aren't good at measuring the number of calories you burn.
一项新的研究结果显示，健康追踪设备在测算卡路里消耗方面，并没有那么准确可靠。

It's probably not a good idea to decide what to eat based on how many calories your wearable fitness tracker says you've burned, according to a new study.
根据这项新研究，如果你还在根据可穿戴设备测算的卡路里消耗，来控制自己的饮食的话，最好别再这么做了。

Researchers at Stanford University in California, who tested several popular fitness trackers on 60 volunteers, say the fitness trackers are good for measuring heart rate and counting steps, but they're bad at measuring energy expenditure.
斯坦福大学的研究者招募了 60 名志愿者，对多款市售主流健康追踪设备进行了测试。测试结果表明，这些设备能够准确测量心率与步数，但并不能准确测算能量消耗。

The volunteers, 29 men and 31 women, engaged in a variety of physical activities, including walking or running on a treadmill or riding a stationary bike. Their heart rates were measured using a medical-grade electrocardiograph. Energy expenditure was determined by measuring the levels of oxygen and carbon dioxide in the volunteers' breath.
这 60 名志愿者由 29 名男性和 31 名女性组成。他们参与了多种运动，包括跑步机步行或跑步、骑健身单车。在运动中，他们的心率通过医用级心电图仪进行测量，能量消耗则通过呼吸中的氧气和二氧化碳含量进行测算。

Six of the seven devices tested, which include the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn and the Samsung Gear S2, did a good job measuring heart rate, coming within 5 percent of the accuracy of the electrocardiograph.
被测设备包括 Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn 以及 Samsung Gear S2 。结果显示，七款设备中，有六款设备能准确测量心率，与心电图仪的误差在 5% 以内。

However, when it came to measuring calories burned, they did not do a very good job, with the most accurate tracker off by 27 percent. One was off by 93 percent.
然而，在测算卡路里消耗方面，这些设备表现不佳，最准确的一款也达到了 27% 的误差，其中一款的误差甚至达到了 93% 。

"People are basing life decisions on the data provided by these devices," said Euan Ashley, a professor of cardiovascular medicine, of genetics and of biomedical data science at Stanford, who added that consumer devices aren't held to the same standards as medical devices.
“人们每天根据这些设备提供的数据来调整生活方式，”斯坦福大学心血管医学、遗传学与生物医学数据科学教授 Euan Ashley 如是说。他补充道，消费级设备并不具备与医用级设备相同的精度标准。

Ashley was surprised by the results.
Ashley 对测试结果非常惊讶。

"The heart rate measurements performed far better than we expected," he said. "But the energy expenditure measures were way off the mark. The magnitude of just how bad they were surprised me."
“这些设备在心率测量方面的表现远超我们的预期，”他说。“但是在能量消耗方面的测算实在离谱，差异之大令我非常惊讶。”

The findings were published May 24 in the Journal of Personalized Medicine.
该项研究结果于 5 月 24 日发表于《个人医学》杂志。