科学美国人60秒:运动手环并不能准确计算卡路里

This is Scientific American — 60-Second Science. I'm Christopher Intagliata. 这里是科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。

Fitness bands like the Apple Watch and the Fitbit aim to track your vitals, like heart rate. 苹果手表和Fitbit等运动手环的设计初衷是追踪你的生命体征，比如心率。

But early models weren't all that accurate. 但是运动手环的早期型号却并不那么精确。

"We thought of them a little bit like random number generators. “我们认为这些手环有点像随机数生成器。

They really didn't seem to be providing anything that bore any relationship to heart rate." 它们似乎并没有提供任何与心率有关的数据。”

Euan Ashley, a cardiologist who studies wearables at Stanford University. 斯坦福大学研究可穿戴设备的心脏病专家尤安·阿什利说道。

He and his colleagues have now tested seven newer fitness bands—from brands like Apple, Fitbit and others— 目前，他和同事已经测试过苹果、Fitbit和其他品牌的7种新型运动手环，

and he says those heart rate stats have gotten way better. 他表示，所监测到的心率数据准确多了。

"Yeah we were pleasantly surprised actually by how good the accuracy of the heart rate monitoring was." “是的，我们对运动手环的心率监测准确性竟然如此之高感到惊喜。”

For most of the devices, the error rate was less than five percent—good enough for your doctor. 大多数手环的错误率小于5%，对你的医生来说这足够好了。

But where all the devices failed to measure up was estimating calories burned. 但是，在估算卡路里消耗值方面，所有运动手环都不合格。

Even the most accurate devices were off by 27 percent, compared to lab measurements of energy expenditure. 与能量消耗的实验室测量值相比，就连最准确的手环也有27%的误差。

One device was off by more than 90 percent. 其中一个手环的差错率甚至超过90%。

"If you think about going to the gym and working out for an hour and maybe that's around 400 calories, “如果你去健身房锻炼一小时，运动手环可能显示你消耗了大约400卡路里，

in reality that could be anything from 200 to 800. 但实际上你的消耗值从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 如果有人将这一数据融入其生活方式当中，

and thinking about what to eat that evening based on the workout they did that afternoon." 依据下午的锻炼情况来决定晚上吃什么，那就有很大差异了。”

The results are in the Journal of Personalized Medicine. 这项研究结果发表在《个性化医学》期刊上。

The reason for the discrepancy, Ashley says, could be that we all burn energy at different rates— 阿什利表示，产生这种差异的原因可能是我们燃烧能量的速率不同，

and that's hard to reckon from simple input stats like weight and height. 而且这很难通过身高体重这类简单的输入数据估算出来。

"Some people are incredibly efficient and look incredibly elegant when they run. “有些人跑步时很优雅，而且还能高效地燃烧能量。

And others really clearly look like they're burning a lot more calories to cover the same amount of ground." 而其他人跑步时则很费力，虽然是跑同样的里数，但看起来却消耗了更多的卡路里。”

So if you own a wearable, it's probably safe to trust the heart data. 因此，如果你有可穿戴设备，它可能会提供安全可信的心率数据。

What it can't tell you is whether your time on the treadmill really justifies that chocolate shake. 但它无法告诉你的是，你在跑步机上的锻炼是否能消耗掉那杯巧克力奶昔的热量。

Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata. 谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。

重点讲解：
1. measure up 符合(标准)；达到(期望)；
例句：It was fatiguing sometimes to try tomeasure up to her standard of perfection.
有时候，力求达到她尽善尽美的标准让人觉得很累。
2. compared to 与…相比；和…比起来；
例句：His progress at school had been unspectacularcompared to his brother.
和弟弟相比，他在学校里的进步很不起眼。
3. work out 锻炼；健身；
例句：While the lads are golfing, I work out in the gym.
小伙子们打高尔夫球的时候，我在健身房锻炼。
4. in reality 事实上；实际上；
例句：He came across as streetwise, but in reality he was not.
他给人的印象是很适应都市生活，但实际上并非如此。