科學家稱運動手環無法準確測量消耗的卡路里
Fitness bands like the Apple Watch and the Fitbit aim to track your vitals, like heart rate. But early models weren't all that accurate.
蘋果手錶和Fitbit等運動手環的設計初衷是追蹤你的生命體徵，比如心率。但是運動手環的早期型號卻並不那麼精確。"We thought of them a little bit like random number generators. They really didn't seem to be providing anything that bore any relationship to heart rate," said Euan Ashley, a cardiologist who studies wearables at Stanford University.
斯坦福大學研究可穿戴設備的心臟病專家尤安·阿什利表示：“我們認爲這些手環有點像隨機數生成器。它們似乎並沒有提供任何與心率有關的數據。”He and his colleagues have now tested seven newer fitness bands -- from brands like Apple, Fitbit and others -- and he says those heart rate stats have gotten way better. "Yeah we were pleasantly surprised actually by how good the accuracy of the heart rate monitoring was."
目前，他和他的同事已經測試過蘋果、Fitbit和其他品牌的7種新型運動手環，他表示，所監測到的心率數據準確多了。“是的，我們對運動手環的心率監測準確性竟然如此之高感到驚喜。”
For most of the devices, the error rate was less than five percent -- good enough for your doctor. But where all the devices failed to measure up was estimating calories burned.
大多數手環的錯誤率小於5%，對你的醫生來說這足夠好了。但是，在估算卡路里消耗值方面，所有運動手環都不合格。
Even the most accurate devices were off by 27 percent, compared to lab measurements of energy expenditure. One device was off by more than 90 percent.
與能量消耗的實驗室測量值相比，就連最準確的手環也有27%的誤差。其中一個手環的差錯率甚至超過90%。If you think about going to the gym and working out for an hour and maybe that's around 400 calories, in reality that could be anything from 200 to 800.
如果你去健身房鍛鍊一小時，運動手環可能顯示你消耗了大約400卡路里，但實際上你的消耗值從200到800卡路里都有可能。And that's a big difference if you're thinking about somebody who's incorporating those estimates into their lifestyle and thinking about what to eat that evening based on the workout they did that afternoon.
如果有人將這一數據融入其生活方式當中，依據下午的鍛鍊情況來決定晚上吃什麼，那就有很大差異了。The reason for the discrepancy, Ashley says, could be that we all burn energy at different rates—and that's hard to reckon from simple input stats like weight and height.
阿什利表示，產生這種差異的原因可能是我們燃燒能量的速率不同，而且這很難通過身高體重這類簡單的輸入數據估算出來。"Some people are incredibly efficient and look incredibly elegant when they run. And others really clearly look like they're burning a lot more calories to cover the same amount of ground," he said.
他說道：“有些人跑步時很優雅，而且還能高效地燃燒能量。而其他人跑步時則很費力，雖然是跑同樣的裏數，但看起來卻消耗了更多的卡路里。”So if you own a wearable, it's probably safe to trust the heart data. What it can't tell you is whether your time on the treadmill really justifies that chocolate shake.
因此，如果你有可穿戴設備，它可能會提供安全可信的心率數據。但它無法告訴你的是，你在跑步機上的鍛鍊是否能消耗掉那杯巧克力奶昔的熱量。
