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Thursday, June 12, 2008

Sleeping Patterns Are Governed by Light (part 3)

Get the Light Out of Your Bedroom

It would serve you well to do a thorough “light check” of your bedroom, as any source of light -- even one as tiny as the green glow from your clock radio -- could be interfering with your ability to sleep, and more importantly, your long term health and risk of developing cancer.

While it’s typically thought that your biological clock is what tells you when it’s time to wake up or go to sleep, light and dark signals actually control your biological clock. To get more specific, a part of your brain called the Suprachiasmatic Nucleus (SCN) -- a group of cells in your hypothalamus -- controls your biological clock. And the cells that make up your SCN respond to light and dark signals.

Light actually travels through your eye’s optic nerve to your SCN, where it signals your body’s clock that it’s time to wake up. Light also signals your SCN to initiate other processes associated with being awake, such as raising your body temperature and producing hormones like cortisol.

Meanwhile, when your eyes signal to your SCN that it’s dark outside, your body will begin to produce melatonin, a hormone that helps you sleep and radically decreases your risk of cancer. There are many studies on this powerful association. The more your sleep is disrupted by light pollution, the lower your melatonin levels and the greater your risk of developing cancer becomes.

Melatonin is secreted primarily in your brain and at night it triggers a host of biochemical activities, including a nocturnal reduction in your body's estrogen levels. It’s thought that chronically decreasing your melatonin production at night -- as occurs when you’re exposed to nighttime light -- increases your risk of developing cancer.

In fact, one of the first studies linking cancer to light showed that blind women have a 36 percent lower risk of breast cancer compared to sighted women. Why? Because they are unreceptive to light. This means that their bodies maintain high melatonin levels at night regardless of how much light is in the room.

It really is a fascinating system.

Source mercola.com

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