Why Do You Get Sleepy When You Drive？

为什么开车时容易犯困？

王淑怡 供稿

Most of us have probably felt sleepy on a car journey, but it's not always due to an early start, or a long day, or a lack of caffeine.

我们大多数人可能在开车过程中会感到困倦，但这并不总是因为起得太早，或经历了漫长的一天，或缺少咖啡因所导致的。

It's all to do with the vibrations a car makes as it moves: they can bring on sleepiness in just 15 minutes, the new study shows. That's something for both car manufacturers and road safety experts to think about, according to the researchers from RMIT University in Australia. They want to conduct further studies into how car seat vibrations could be secretly bringing on sleep.

一项新的研究表明，这与汽车行驶时产生的振动有关，振动可以在短短15分钟内让人产生困意。澳大利亚皇家墨尔本理工大学的研究人员表示，这是汽车制造商和道路安全专家需要思考的问题。他们希望进一步研究汽车座椅的振动是如何在不知不觉中让人昏昏欲睡的。

"When you're tired, it doesn't take much to start nodding off and we've found that the gentle vibrations made by car seats as you drive can lull your brain and body," says one of the team, Stephen Robinson. "Our study shows steady vibrations at low frequencies – the kind we experience when driving cars and trucks – progressively induce sleepiness even among people who are well rested and healthy."

“在很累的情况下，人们很容易就会打瞌睡。我们发现，驾驶过程中汽车座椅产生的轻微振动可以使人的大脑和身体得到放松，”该团队一名研究人员斯蒂芬·罗宾逊说，“我们的研究表明，即便是休息良好且身体健康的司机，当驾驶汽车或卡车时，汽车座椅低频率的轻微振动也会逐渐诱发困意。”

Robinson and his colleagues hooked 15 volunteers up to a virtual simulator that they could vibrate at different frequencies. The volunteers were tested twice, once with no vibration, and once with low-frequency 4-7 Hz vibrations. They then measured the heart rate variability (HRV) of the participants.

罗宾逊和他的同事们将15名志愿者与虚拟模拟器连接起来，该模拟器可以产生不同频率的振动。志愿者们分别进行了两次测试，一次是4-7赫兹的低频振动，一次无振动，随后立即测量他们的心率变异性（HRV）。

These researchers discovered that levels of alertness after driving for only 15 min begin to decrease dramatically, and by 30 minutes will have a significant impact on your ability to stay alert and concentrate on the road. By 60 minutes sleepiness was at its peak. However, with tiredness a factor in around 1 in 5 fatal accidents on the road, it's important to make further studies. The researchers want to continue their work by looking at bigger groups of people and more ranges of frequencies.

研究员们发现，仅仅在驾车15分钟后，司机的警觉性就开始大幅降低，30分钟后司机的注意力和警觉能力受到巨大影响，而在60分钟后驾驶员的困意达到最高点。不过，由于五分之一的致命交通事故都是由疲劳驾驶引起的，还需要对此进行更深入的研究。研究员们表示，希望能够继续针对更大范围的群体以及更多波段的频率进行研究。

This is the first study to investigate the effects of whole-body vibration on seated human alertness and drowsiness. The data clearly demonstrate that exposure to vibration has considerable influence on subjective sleepiness levels, and more importantly, human reaction times and lapses of attention.

此项研究首次调查了坐着的人在受到全身振动时其警觉性和睡意受到的影响。数据清楚地表明，振动对主观嗜睡水平有很大的影响，更重要的是，对人类的反应时间和注意力缺失也有显著影响。

These findings need to be further consolidated particularly in relation to driving behavior. This line of research can then assist in the development of practical and relevant guidelines for limitation of vibration exposure in the automotive industry, in an effort to reduce the burden of road accidents.

上述研究结果还需要得到进一步的证实，特别是与驾驶行为相关的方面。这些研究将有助于制定实用的指南以指导汽车制造业限制振动程度，从而达到减少道路事故的目的。

VOCABULARY

1. vibration n. 震动；颤动；抖动；（感情的）共鸣

2. nod off  打盹

3. lull v. 使放松；使镇静

4. heart rate variability 心率变异性

5. drowsiness n. 睡意；困倦；假寐

6. lapse n.  (一时的) 走神; 判断错误

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