[LINK] Melatonin

[stephen at melbpc.org.au]

Bright Screens Could Delay Bedtime 

By Stephani Sutherland <http://www.scientificamerican.com/article.cfm?
id=bright-screens-could-delay-bedtime>


If you have trouble sleeping, laptop or tablet use at bedtime might be to 
blame, new research suggests. 

Mariana Figueiro of the Lighting Research Center at Rensselaer 
Polytechnic Institute and her team showed that two hours of iPad use at 
maximum brightness was enough to suppress people's normal nighttime 
release of melatonin (a key hormone in the body's clock) or circadian 
system. 

Melatonin tells your body that it is night, helping to make you sleepy. 

If you delay that signal, Figueiro says, you could delay sleep. 

Other research indicates that, "if you do that chronically, for years, it 
can lead to disruption of the circadian system," sometimes with serious 
health consequences, she explains.

The dose of light is important, Figueiro says; the brightness and 
exposure time, as well as the wavelength, determine whether it affects 
melatonin. 

Light in the blue-and-white range emitted by today's tablets can do the 
trick — as can laptops and desktop computers, which emit even more of the 
disrupting light but are usually positioned farther from the eyes, which 
ameliorates the light's effects. The team designed light-detector goggles 
and had subjects wear them during late-evening tablet use. The light dose 
measurements from the goggles correlated with hampered melatonin 
production.

On the bright side, a morning shot of screen time could be used as light 
therapy for seasonal affective disorder and other light-based problems. 

Figueiro hopes manufacturers will "get creative" with tomorrow's tablets, 
making them more "circadian friendly," perhaps even switching to white 
text on a black screen at night to minimize the light dose (or) turn down 
the brightness of glowing screens (late at night) before bed ..

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Cheers,
Stephen