斯坦福大学的新研究发现，老年人保持正常的睡眠时间很重要。如果睡眠时间不足6个小时，患痴呆症的风险会增加；如果睡眠时间超过9个小时，大脑执行力会变差。

Older adults who sleep six hours or fewer a night may have elevated risk for dementia and other cognitive issues, a new study finds.

一项新研究发现，每晚睡眠时间在6个小时以下的老年人患痴呆症和其他认知障碍的风险会增高。

Researchers at Stanford University measured seniors' (ages 65 to 85) dementia risk and cognitive abilities, finding higher risk in those patients who regularly slept six or fewer hours compared to those who slept seven or eight hours.

斯坦福大学的研究人员通过对年龄在65岁到85岁之间的老年人的痴呆风险和认知能力测评发现，平时睡眠6个小时以下的人相比睡7个或8个小时的人痴呆风险更高。

Those seniors who slept nine or more hours also had lower cognitive functions and other health issues, but the researchers didn't find the same high dementia risk in this group.

平时睡9个小时以上的人也出现了认知能力低下和其他健康问题，但是研究人员发现该群体的痴呆风险不像睡眠不足的人群这么高。

The findings demonstrate how important it is for adults to maintain a healthy sleep cycle, especially as they get older.

研究结果表明，成年人保持一个健康的睡眠周期有多么重要，尤其在步入老年之后。

As adults age, it's common for their sleep patterns to change or become disrupted - leading to longer, shorter, or more irregular sleep.

随着年纪增长，成年人的睡眠模式通常会发生改变或出现紊乱，从而导致睡眠时间变长、变短或变得不规律。

This disruption may be linked to Alzheimer's and other forms of dementia, impacting seniors' ability to remember information, problem-solve, and go through everyday behaviors.

睡眠紊乱可能和老年痴呆症或其他类型的痴呆症有关，影响着老年人记忆信息、解决问题的能力，并会影响日常行为。

Sleep disruption can also be caused by - or heighten - depression, cardiovascular disease, and other conditions.

睡眠紊乱还可能由抑郁症、冠心病和其他疾病导致或加剧这些病症。

New research from Stanford University provides additional evidence for the connection between sleep and brain function. The study was published Monday in JAMA Neurology.

斯坦福大学的这项新研究为睡眠和大脑功能之间的联系提供了新证据。该研究本周一（8月30日）发表在《美国医学会神经病学杂志》上。

The Stanford study included health records from about 4,400 patients, all between the ages of 65 and 85. These patients had undergone brain scans and other cognitive tests, but hadn't been diagnosed with dementia.

斯坦福大学的这项研究包含了年龄在65岁到85岁之间的约4400名患者的健康记录。这些患者都接受了大脑扫描和其他认知测试，但是都还未被确诊为痴呆症。

This data was drawn from a long-term Alzheimer's investigation, conducted at 67 clinics in the US, Canada, Australia, and Japan.

研究所用的数据来自一项长期的痴呆症调查，该调查在美国、加拿大、澳大利亚和日本的67个诊所开展。

The researchers grouped these patients according to how long they typically slept. Sleep times were self-reported by the patients, not measured by a sleep tracker.

研究人员根据患者平时的睡眠时间给他们进行分组。睡眠时间是由患者自己报告的，而不是由睡眠跟踪器记录的。

A recommended sleep time for seniors is seven to eight hours, the researchers said. Six or fewer hours corresponded to short sleep, while nine or more hours corresponded to long sleep.

研究人员称，老年人的最佳睡眠时间是7到8个小时。6个或6个小时以下属于睡眠时间过短，9个小时以上则被定义为睡眠时间过长。

The Stanford researchers measured levels of beta amyloid, a protein in the brain that is typically found in high levels when a patient develops Alzheimer's.

斯坦福大学的研究人员测量了名为β淀粉样蛋白的大脑蛋白质的水平，这种蛋白质通常在老年痴呆症患者大脑中会大量出现。

In addition, the researchers used several tests for memory, attention, spatial skills, and executive function to identify patients' cognitive abilities.

此外，研究人员还测试了记忆力、注意力、空间感知力和执行力来评定患者的认知能力。

Those patients sleeping for six hours or fewer a night were more likely to develop dementia, the researchers found. The low-sleep patients had higher levels of beta amyloid.

研究人员发现，睡眠时间在6个小时以内的患者更容易患痴呆症。这些睡眠少的患者大脑中的β淀粉样蛋白含量更高。

'Amyloid-β is one of the first detectable markers in the progression of Alzheimer's disease,' Joe Winer, postdoctoral researcher at Stanford and the study's lead author, told CNN.

该研究的首席作者、斯坦福大学的博士后研究员乔·维纳告诉美国有线电视新闻网说：“β淀粉样蛋白是痴呆症病程进展中最早可察觉到的标记物之一。”

The Stanford researchers found that patients with lower sleep also performed worse on memory tests, while those with higher sleep (nine or more hours) performed worse on executive function tests - which measure the brain's ability to switch between different tasks.

斯坦福大学的研究人员发现，睡眠少的患者在记忆测试中表现更差，而睡眠多（睡眠时间在9个小时以上）的患者在执行力测试中表现更差。执行力测试用于衡量大脑在不同任务之间转换的能力。

Both the low and high sleep patients were more likely to nap during the day, the researchers found. Low-sleep patients may have been compensating for a lack of sleep at night, while high-sleep patients may have simply been drowsy throughout the day.

研究人员发现，睡眠少和睡眠多的患者都更容易在白天打盹。睡眠少的患者可能是在补夜里缺的觉，而睡眠多的人可能只是一整天都昏昏欲睡。

In addition, both the low and high sleep patients had higher body mass index and symptoms of depression.

此外，睡眠少和睡眠多的患者身体质量指数都偏高，出现抑郁症状的比例也更高。

'The main takeaway is that it is important to maintain healthy sleep late in life,' Winer told CNN.

维纳告诉美国有线电视新闻网说：“研究带给我们的主要启示在于，老年人保持健康的睡眠很重要。”