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翻译自Study: Fitness Trackers Accurate for Heart Rate, Not Calories

• 译文如下

研究发现健康追踪器能准确的测量心率，而不是卡路里

如果你认为在你的手腕进行健康追踪给了你一个很好借口来吃甜食，你可能想要再重新思考一下。斯坦福大学医学院最近的一项研究表明，身体追踪器不能很准确的追踪卡路里。这项研究称，然而，健身追踪器可以准确测量心率。
斯坦福研究者调查了当人们在休息和锻炼时候的测量记录。
研究调查者之一的Euan Ashley说，“人们在基于这些设备提供的数据来做生活的决定”。
这项研究查看七款戴在手腕上的健身追踪器：
他们是Apple Watch，Basis Peak（版本1），Fitbit Surge 和 Microsoft Band（版本1）。其它的三个是Mio Alpha 2, PulseOn，和Samsung Gear S2。
60位男女参与者在他们坐立以及在跑步机和健身单车上锻炼时，手腕上佩戴了高达四款追踪器。这些参与者由不同体型和健康水平的人组成。
在从坐到慢跑到跑步的一系列活动中，追踪器测量了心率和热量消耗，或卡路里燃烧。它们也测量了这些人在不同速度下骑自行车的情况。
专业的医疗仪器测量了参与者的心率和呼吸频率，以及体温和血压。这些研究者对比了健康追踪器和那些“黄金标准医疗器械”的监测情况。
能量消耗（EE）
上周发布了最终研究报告。研究发现对于能量测量，没有一款追踪器达到研究者所考虑的可接受误差范围。可接受的误差比例是百分之五以下。
研究者写道，Fibit Surge是热量消耗测量最准确的追踪器。它有平均27.4%的误差率。研究发现PulseOn追踪器最不准确，有92.6%的误差率。
所有的健康追踪器测试发现男性误差率高于女性。所有追踪器在所有形式的锻炼情况下，平均误差率男性高于女性4%。
心率（HR）
好消息是，这些测试的健身追踪器测量心率很准确。除了一款健身追踪器之外，其它所有的追踪器都满足心率测量误差范围。
在研究的追踪器中，Apple Watch在心率测量方面是最准确的，平均2%的误差率。Samsung Gear S2准确度最低，平均误差接近7%。
研究发现
对于能量消耗和心率的测量，研究人员表示“Apple Watch拥有最有利的误差文档，而Samsung Gear S2是最不利的”。
更多的信息
斯坦福研究者还在继续对健康追踪器调查。下一步，他们将测试参与者在他们日常生活和实验室以外锻炼的时候佩戴健康追踪器。
这次完整的研究在《个性化医学杂志》网站上可以看到。

• 原文如下

Study: Fitness Trackers Accurate for Heart Rate, Not Calories

If you think your fitness tracker on your wrist is giving you a good excuse to eat that sweet treat, you may want to think again. A recent study from the Stanford University School of Medicine says fitness trackers are not accurate at tracking calories. The study says, however, that the trackers are accurate at measuring heart rate.

The Stanford researchers examined measurements recorded when people were at rest and while they exercised.

"People are basing life decisions on the data provided by these devices," said Euan Ashley, one of the study investigators.

The study looked at seven fitness trackers worn on the wrist:

They were Apple Watch, Basis Peak (version 1), Fitbit Surge and Microsoft Band (version 1). The others three were Mio Alpha 2, PulseOn, and Samsung Gear S2.

Sixty participants of both sexes wore up to four trackers on their wrists as they sat, and as they exercised on a treadmill and a stationary bike. The participants were a mix of sizes and fitness levels.

The trackers measured the heart rates and energy used, or calorie burn, in activities from sitting to a slow walk to a run. They also tested people cycling at different speeds.

Professional medical instruments measured participants' heart and breathing rates as well as temperature and blood pressure. The researchers compared the fitness tracker measurements to those of the "gold standard medical instruments."

Energy expended (EE)
The final report on the study was published last week. It found that none of the trackers met what researchers considered an acceptable error rate for energy use measurement. The acceptable error rate is five percent or less.
The researchers wrote that the Fitbit Surge was the most accurate tracker of energy use. It had a 27.4 percent average error rate. The study found the PulseOn to be the least accurate tracker, with a 92.6 percent error rate.
The error rate was higher for males than for females with all fitness trackers tested. The average error rate for all the trackers studied under all forms of exercise was four percent higher for males than for females.
Heart rate (HR)

The good news is the tested fitness trackers were accurate at measuring heart rate. All but one of the trackers met the acceptable error rate limit in heart rate measurement.

Of the trackers studied, the Apple Watch was the most accurate at measuring heart rate, with an average error rate of two percent. The Samsung Gear S2 was the least accurate with an average error rate of close to seven percent.

Study findings

For both the measurement of energy used and heart rate, the researchers said "the Apple Watch had the most favorable error profile while the Samsung Gear S2 had the least."
More information

The Stanford researchers are continuing their investigation of fitness trackers. Next, they will test participants wearing fitness trackers during their daily lives and while exercising outside a laboratory.

The full study is available online at The Journal of Personalized Medicine.