久坐让人变傻

Researchers have discovered those with a sedentary lifestyle have a smaller brain region important in forming memories.

The study, by researchers at the University of California in Los Angeles, adds to a growing list about the dangers of sitting for too long.

An array of evidence has already linked the bad habit to heart disease, diabetes, several forms of cancer and an early death in recent years.

But the new research, derived from 35 participants, suggests sitting for too long could even boost the risk of dementia.

Those with the lazy lifestyles had less gray matter in the medial temporal lobe (MTL) — even if they went for regular brisk walks, cycle rides or jogs.

A decline in this area has repeatedly been shown to be an early warning sign of Alzheimer’s disease in middle-aged and elderly patients. The study, published in PLOS ONE, quizzed the volunteers, who were aged between 45 and 75, about their levels of exercise.

Each person underwent a high-resolution MRI scan which provides a detailed look at the MTL, an area involved in the formation of new memories.

The researchers, led by biostatistician Prabha Siddarth, found that sedentary people had a thinner MTL.

Siddarth and colleagues revealed how this finding remained true — even when volunteers had high levels of physical activity.

The researchers warned that the study “does not prove too much sitting causes thinner brain structures.”

However, they were keen to add the research does prove “that more hours spent sitting are associated with thinner regions.”

The researchers wrote, “MTL thinning can be a precursor to cognitive decline and dementia in middle aged and older adults.

“Reducing sedentary behavior may be a possible target for interventions designed to improve brain health in people at risk for Alzheimer’s disease.”

Previous research shows physical activity correlates with higher volume in the hippocampus, a small, memory-critical region deep within the brain. The temporal lobes are on either side of the brain, near the temples. They deal with memory, including recognition of faces and objects and language.

Words to Learn

相关词汇

【久坐的】

jiǔzuò de

sedentary doing or requiring much sitting

【先兆】

xiānzhào

precursor one that precedes and indicates the approach of another

研究人员发现，那些习惯久坐的人的大脑中负责形成记忆的区域更小。

长期久坐的危害有很多，加州大学洛杉矶分校的研究人员开展的这项研究又揭示了久坐的一个新危害。

近些年有大量证据显示，久坐这一坏习惯和心脏病、糖尿病、几种癌症和早逝有关。

新研究调查了35名参与者，结果显示，久坐甚至会增加患老年痴呆症的风险。

经常久坐不动的人即使定期快走、骑车或慢跑，大脑内侧颞叶的灰色神经组织也比不久坐的人更少。

中老年人大脑内侧颞叶的萎缩已被反复证实是患上老年痴呆症的早期迹象。

这项发表在《公共科学图书馆·综合》期刊上的研究对年龄在45岁到75岁之间的志愿者就其锻炼水平进行了问卷调查。

每个人都接受了高分辨率核磁共振成像扫描，研究人员还仔细查看了他们的大脑内侧颞叶——负责形成新记忆的区域。

生物统计学家普拉布哈·西达斯博士领头的研究团队发现，久坐的人大脑内侧颞叶更薄。

西达斯博士和他的同事指出，即使志愿者运动量大，这一结果也不会改变。

研究人员警告说，该研究“没有证明久坐会导致大脑内侧颞叶变薄”。但是，他们马上补充道，研究确实证明“久坐和大脑内侧颞叶变薄有关”。

研究人员写道：“大脑内侧颞叶变薄预示着认知能力的下降和中老年痴呆。”

“减少久坐时间也许是一个可以帮助老年痴呆风险人群改善大脑健康的目标介入手段。”

先前的研究显示，身体活动与更大的海马体有关，海马体是大脑深处和记忆密切相关的一小块区域。

大脑两侧临近太阳穴的颞叶掌管着记忆，包括对脸、物体和语言的辨识。

(chinadaily.com.cn)