Source: VOA
Date: May 26, 2017

A new study suggests fitness trackers aren't good at measuring the number of calories you burn.
一項新的研究結果顯示，健康追蹤設備在測算卡路里消耗方面，并沒有那么準確可靠。

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.
根據這項新研究，如果你還在根據可穿戴設備測算的卡路里消耗，來控制自己的飲食的話，最好別再這么做了。

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.
斯坦福大學的研究者招募了 60 名志愿者，對多款市售主流健康追蹤設備進行了測試。測試結果表明，這些設備能夠準確測量心率與步數，但并不能準確測算能量消耗。

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.
這 60 名志愿者由 29 名男性和 31 名女性組成。他們參與了多種運動，包括跑步機步行或跑步、騎健身單車。在運動中，他們的心率通過醫(yī)用級心電圖儀進行測量，能量消耗則通過呼吸中的氧氣和二氧化碳含量進行測算。

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.
被測設備包括 Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn 以及 Samsung Gear S2 。結果顯示，七款設備中，有六款設備能準確測量心率，與心電圖儀的誤差在 5% 以內。

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，在測算卡路里消耗方面，這些設備表現不佳，最準確的一款也達到了 27% 的誤差，其中一款的誤差甚至達到了 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.
“人們每天根據這些設備提供的數據來調整生活方式，”斯坦福大學心血管醫(yī)學、遺傳學與生物醫(yī)學數據科學教授 Euan Ashley 如是說。他補充道，消費級設備并不具備與醫(yī)用級設備相同的精度標準。

Ashley was surprised by the results.
Ashley 對測試結果非常驚訝。

"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."
“這些設備在心率測量方面的表現遠超我們的預期，”他說。“但是在能量消耗方面的測算實在離譜，差異之大令我非常驚訝。”

The findings were published May 24 in the Journal of Personalized Medicine.
該項研究結果于 5 月 24 日發(fā)表于《個人醫(yī)學》雜志。