Children as young as six are risking heart problems in later life because they are allowed to spend too much time watching TV or playing on computers, scientists warn.
A study of 1,492 primary school pupils found that those who spent hours glued to the screen suffered narrowing of blood vessels in their eyes - an early warning sign of increased likelihood of heart disease and high blood pressure.
But those who exercised for one hour a day were significantly healthier.
The study was carried out by Dr Bamini Gopinath and a team of researchers at the University of Sydney.
Parents answered a questionnaire detailing the amount of time their children spent watching TV, playing video games, reading and engaging in indoor and outdoor physical activity.
Scientists then took digital photographs of the blood vessels at the back of each child's eye and calculated their size.
They also measured height, weight, body mass index and blood pressure.
They found on average, children spent 1.9 hours per day watching TV or playing on their computer and only 36 minutes doing physical activity.
They had an average "retinal arteriolar" narrowing of 2.3 microns.
But those who regularly participated in outdoor physical activity had retinal blood vessels that were 2.2 microns wider.
Dr Gopinath said that "replacing one hour a day of screen time with physical activity" could be enough to stop the effects.


科学家们警告，就算只是六岁的小孩，但如果每天看电视玩电脑的时间没有节制的话，在他们长大成人之后，患上心脏病的几率将提高。

一份调查报告研究了1492名小学生，发现那些花数小时盯着屏幕的孩子出现了眼部血管紧张的迹象，这位认为是患上心脏方面疾病以及高血压的先前预兆。

但那些每天运动时间达到一小时的孩子却要健康的多。
这份研究是由悉尼大学的Bamini Gopinath博士以及他的团队所进行的。

他们详细的询问家长关于孩子花在每天看电视、玩电玩上的时间，以及他们阅读和参加户外体育锻炼的情况。

然后科学家们拍摄下了孩子们后眼血管的数码图像，并分析了血管的大小。
同时他们还测量了身高、体重、身体质量以及血压。
研究者发现，这些孩子平均每天观看电视和玩电脑的时间达到1.9个小时，而参加体育运动的时间仅有36分钟。
他们的视网膜神经平均缩小了2.3微米。

但那些定期参加户外体育活动的孩子的视网膜神经则更宽上2.2微米。

Gopinath说："每天多一小时的体育锻炼，这将有效的缓解由于长期看电视和玩电脑所造成的对于身体的伤害，"

• primary [´praiməri] a.主要的 n.居首位的 (初中英语单词)
• screen [skri:n] n.银幕 vt.遮蔽 (初中英语单词)
• amount [ə´maunt] n.总数；数量 v.合计 (初中英语单词)
• reading [´ri:diŋ] n.(阅)读；朗读；读物 (初中英语单词)
• physical [´fizikəl] a.物质的；有形的 (初中英语单词)
• height [hait] n.高度；顶点；卓越 (初中英语单词)
• computer [kəm´pju:tə] n.计算机；电子计算器 (初中英语单词)
• regularly [´regjuləli] ad.有规律地；经常地 (高中英语单词)
• warning [´wɔ:niŋ] n.警告；前兆 a.预告的 (英语四级单词)
• likelihood [´laiklihud] n.可能，相似性 (英语六级单词)