科学家说 黑暗有益于健康
晚上从卫星上看，整个北美洲是发光的，为发光数十亿美元正在被浪费。不过，人们对此已经习以为常了。但是人们并没有意识到，因人工光线造成黑暗消失事实上对我们的健康有破坏性的作用。科学研究结果表明：当我们尽力消除夜晚的黑暗时，我们也失去了黑暗对安全和健康的自然促进作用。因为黑暗可以抗癌、拯救鸟类生命、阻止涂鸦行为等。
·人体需要黑暗
夜晚的黑暗使得某些癌症得以控制，这是大自然赋予我们的一种天生防癌功能。光生物学家说，褪黑色素可阻止包括乳腺癌和前列腺癌在内的癌细胞生长。人体只有在完全黑暗的环境中才会产生这种激素。如果夜晚你的床周有一点点光，褪黑色素就会停止产生。夜晚看电视，人体也会启动只在白天才被激活的免疫系统激素，使其耗竭，从而导致机体更易患感冒。
·大自然需要黑暗
, http://www.100md.com
大量的光在夜空中闪耀会遮蔽了星光，如果用反射镜将这些光线聚中起来就可以起到防护作用。晚上仅仅将办公大楼和学校系统的灯关上，每年就可节省百万美元。芝加哥的世界最高的西尔思高楼为了拯救鸟类，每晚不得不关灯，因为每年数百万的迁徙鸟类会被灯光吸引，飞进这座建筑物而撞死。
·社会需要黑暗
警察称黑暗有时反而更安全。因为如果晚上都不开灯，当看见一座建筑物突然有灯光时，邻居就会有所警惕甚至报警。而且黑暗也会会减少涂鸦行为，因为通常只有有光亮的墙才会吸引那些无聊的人去涂鸦。
Scientists Say Darkness Benefits Health
Can darkness help keep cancer at bay? Can it save the lives of birds? Can it cut down on some grafitti? You betcha. Find out why, and what else it can do besides save energy.
, 百拇医药
Look at North America from a satellite at night and it glows, with billions of wasted energy dollars.
Nobody meant this to happen, and it‘s having a devastating effect on our health.
It turns out we need the darkness to make our immune systems work.
Darkness for Health
Scientists have now discovered that only when it‘s really dark can your body produce the hormone called melatonin. Melatonin fights diseases, including breast and prostate cancer.
, http://www.100md.com
"It turns off the cancer cells from growing," says Joan Roberts, a photo biologist.
But if there‘s even a little light around your bed at night, your melatonin production switches off.
"So there may be this natural way that Mother Nature has given us, that is, dark night to keep certain cancers under control," Roberts says.
Even watching TV turns on other immune system hormones that should be active only in daytime. They get depleted, and you‘re more likely to get a cold.
, 百拇医药
Nature needs darkness, too.
The immune systems of animals grow weak if there‘s artificial light at night.
Switching Off
It turns out that‘s easy to fix. Lights that spill so much glare up into the sky that it even wipes out the stars can be shielded with reflectors to focus on the light and make them more efficient. Or, you can simply switch off the lights.
, http://www.100md.com For example, by going dark at night, some office buildings and school systems are each now saving as much as $1 million a year.
At the Sears Tower in Chicago, they are turning out the lights to save the birds. Millions of migrating birds die every year when they are attracted to the lights and fly into the buildings.
And there‘s another surprise: Police report that such darkness is often safer. That‘s partly because neighbors soon learn to alert police if they see any lights on in a building. There‘s even less graffiti because it‘s usually lighted walls that attract the spray-can vandals, not dark ones.
Around Tucson, Ariz., the site of observatories and where law requires that lights focus down only on what needs to be lighted, people have even discovered the stars again. Some say they‘ve also discovered how much we lost when we wiped out dark night and its natural promotion of safety and health., 百拇医药
·人体需要黑暗
夜晚的黑暗使得某些癌症得以控制，这是大自然赋予我们的一种天生防癌功能。光生物学家说，褪黑色素可阻止包括乳腺癌和前列腺癌在内的癌细胞生长。人体只有在完全黑暗的环境中才会产生这种激素。如果夜晚你的床周有一点点光，褪黑色素就会停止产生。夜晚看电视，人体也会启动只在白天才被激活的免疫系统激素，使其耗竭，从而导致机体更易患感冒。
·大自然需要黑暗
, http://www.100md.com
大量的光在夜空中闪耀会遮蔽了星光，如果用反射镜将这些光线聚中起来就可以起到防护作用。晚上仅仅将办公大楼和学校系统的灯关上，每年就可节省百万美元。芝加哥的世界最高的西尔思高楼为了拯救鸟类，每晚不得不关灯，因为每年数百万的迁徙鸟类会被灯光吸引，飞进这座建筑物而撞死。
·社会需要黑暗
警察称黑暗有时反而更安全。因为如果晚上都不开灯，当看见一座建筑物突然有灯光时，邻居就会有所警惕甚至报警。而且黑暗也会会减少涂鸦行为，因为通常只有有光亮的墙才会吸引那些无聊的人去涂鸦。
Scientists Say Darkness Benefits Health
Can darkness help keep cancer at bay? Can it save the lives of birds? Can it cut down on some grafitti? You betcha. Find out why, and what else it can do besides save energy.
, 百拇医药
Look at North America from a satellite at night and it glows, with billions of wasted energy dollars.
Nobody meant this to happen, and it‘s having a devastating effect on our health.
It turns out we need the darkness to make our immune systems work.
Darkness for Health
Scientists have now discovered that only when it‘s really dark can your body produce the hormone called melatonin. Melatonin fights diseases, including breast and prostate cancer.
, http://www.100md.com
"It turns off the cancer cells from growing," says Joan Roberts, a photo biologist.
But if there‘s even a little light around your bed at night, your melatonin production switches off.
"So there may be this natural way that Mother Nature has given us, that is, dark night to keep certain cancers under control," Roberts says.
Even watching TV turns on other immune system hormones that should be active only in daytime. They get depleted, and you‘re more likely to get a cold.
, 百拇医药
Nature needs darkness, too.
The immune systems of animals grow weak if there‘s artificial light at night.
Switching Off
It turns out that‘s easy to fix. Lights that spill so much glare up into the sky that it even wipes out the stars can be shielded with reflectors to focus on the light and make them more efficient. Or, you can simply switch off the lights.
, http://www.100md.com For example, by going dark at night, some office buildings and school systems are each now saving as much as $1 million a year.
At the Sears Tower in Chicago, they are turning out the lights to save the birds. Millions of migrating birds die every year when they are attracted to the lights and fly into the buildings.
And there‘s another surprise: Police report that such darkness is often safer. That‘s partly because neighbors soon learn to alert police if they see any lights on in a building. There‘s even less graffiti because it‘s usually lighted walls that attract the spray-can vandals, not dark ones.
Around Tucson, Ariz., the site of observatories and where law requires that lights focus down only on what needs to be lighted, people have even discovered the stars again. Some say they‘ve also discovered how much we lost when we wiped out dark night and its natural promotion of safety and health., 百拇医药