How Much Sleep Do You Really Need?
您真正需要多少睡眠？

How many hours do you need to sleep each night to stay healthy?
您每晚需要睡多少小时才能保持健康？

The National Sleep Foundation’s sleep time duration recommendations are pretty clear. The sleep experts suggest that the appropriate sleep duration for teenagers is eight to ten hours per night, while it is seven to nine hours for young adults and adults, and seven to eight hours for older adults. Thus, they consistently recommend getting seven hours or more of sleep per night, no matter which age group you are in.
美国国家睡眠基金会的睡眠持续时间建议非常明确。睡眠专家建议，青少年的适当睡眠时间为每晚 8 到 10 小时，而年轻人和成年人为 7 到 9 小时，老年人为 7 到 8 小时。因此，无论您处于哪个年龄段，他们始终建议每晚睡 7 小时或更长时间。

The results of a new multinational neuroscience study now question this recommendation. In the study, the authors collected the sleep duration data of 613 participants over an impressive period of 28 years. Data collection took place from 1985 to 2013. Based on their sleep duration, participants were categorized into four different groups: “five hours or less”, “six hours”, “seven hours” or “eight hours”. Each participant had to perform a number of tests to assess their cognitive abilities. These tests included a wide variety of cognitive abilities like memory, higher cognitive functions and reaction times. In addition, the researcher used a magnetic resonance imaging (MRI) scanner to assess several aspects of brain structure. These included the structure of the grey matter of the brain, i.e. the areas of the brains that mainly contain the cell bodies of neurons. Moreover, the structure of the white matter of the brain, i.e. the neural connections between different grey matter regions, was assessed.
一项新的跨国神经科学研究的结果现在质疑这一建议。在这项研究中，作者收集了 613 名参与者在 28 年的令人印象深刻的时间内的睡眠持续时间数据。数据收集于 1985 年至 2013 年进行。根据他们的睡眠时间，参与者被分为四个不同的组：“5 小时或更短”、“6 小时”、“7 小时”或“8 小时”。每个参与者都必须进行一些测试来评估他们的认知能力。这些测试包括各种认知能力，如记忆力、更高的认知功能和反应时间。此外，研究人员使用磁共振成像 （MRI） 扫描仪来评估大脑结构的几个方面。这些包括大脑灰质的结构，即大脑中主要包含神经元细胞体的区域。此外，还评估了大脑白质的结构，即不同灰质区域之间的神经连接。

The authors had the hypothesis that people who consistently slept at least seven hours per night would have improved cognition as well as improved grey matter and white matter structure than those people who consistently slept less than the guidelines recommend.
作者的假设是，与持续睡眠时间少于指南建议的人相比，每晚持续睡眠至少 7 小时的人会改善认知能力，并改善灰质和白质结构。

The results, however, were quite surprising.
然而，结果却相当令人惊讶。

In general, they found that for most people sleep duration remained relatively stable over 28 years. About 12.7 percent of the participants slept eight hours, about 45.4 percent slept seven hours, 37.2 percent slept six hours and 4.7 percent slept five hours each night.
一般来说，他们发现对于大多数人来说，睡眠时间在 28 年内保持相对稳定。大约 12.7% 的参与者每晚睡 8 小时，大约 45.4% 的人睡 7 小时，37.2% 的人睡 6 小时，4.7% 的人每晚睡 5小时。

Remarkably, there were absolutely no differences in cognition or any of the brain parameters between the different sleep duration groups. Thus, sleeping six or even five hours each night was not associated with impaired cognition or any negative effects on the brain. The authors suggested that it might be more meaningful to also analyze sleep quality when assessing the impact of sleep on cognition and brain structure. Moreover, this suggested that current sleep duration guidelines might need to be redesigned if further studies support their results. (515 words)
值得注意的是，不同睡眠持续时间组之间的认知或任何大脑参数绝对没有差异。因此，每晚睡 6 小时甚至 5 小时与认知障碍或对大脑的任何负面影响无关。作者建议，在评估睡眠对认知和大脑结构的影响时，分析睡眠质量可能更有意义。此外，这表明如果进一步的研究支持他们的结果，则可能需要重新设计当前的睡眠持续时间指南。（515 字）