Light Exposure And Its Affects On Sleep

[davekm]

A program called flux looks great for late evening/night computer users. It gradually lowers the color temperature of your monitor.

Edited August 15, 2012 by davekm

[maddog]

I'm not looking to increase melatonin. Just stop blue light from decreasing it. In that sense, I think it's a good idea to decrease late night blue light exposure.

Whats spectra? Is that the wattage?

Think range of frequencies. Say (wavelength) {430 nm, 435 nm, 438 nm, 442 nm ...} This is a viable spectra (measured in wavelength instead frequencies).

Since c = "lambda" * f, it is easy to determine frequencies from wavelength for light.

 

maddog

Edited August 15, 2012 by maddog

[davekm]

deleted...

Edited January 7, 2014 by davekm

[davekm]

I have checked the sunset and rise for my city of residence, Sheffield, UK. There is only a 7 hour gap from sunset to sunrise in June, a 7 1/2 hour gap in July and a 8 hour 6 min gap in May. This challenges the assertion that you need 8 hrs of sleep in the summer. Our circadian rhythm evolved from homo sapiens who slept when it became dark. Furthermore, it stays light for an hour after sunset. So to follow your natural circadian pattern in the UK, you would only get 6-7 hours sleep in the summer. Likewise, there is a 16 1/2 hr period till sunrise in December, suggesting we should almost hibernate in the winter.

 

I guess I really need to know the sunrise and sunset that we evolved to. I know homo-sapiens have the PER3 gene, I don't know if homo-erectus did though. If our biological clock was evolved from homo-sapiens that would mean we followed the sunset hours of Africa. I'm not sure what those sunset hours were, as the equator has moved as much as 110 km over the past million years. On top of that, the continents move about 20 kilometers per million years, some places move 70 kilometers per year. So I doubt I could predict past sunlight hours based on modern equatorial Africa, which is around 12 hours of sun daily.

 

With the melatonin and light mechanism being an evolutionary thing, I wonder if we should return to waking up at sunrise and sleeping at sunset, work permitting of course. Or as close as possible. There are also links between proper circadian rhytym and longevity. This corresponds with rodent studies which shows melatonin increases longevity.

 

Here is the sunset and sunrise in Sheffield UK in the middle of the month -

Rise Set Hours of Daylight

Jan 8:13 16:17 8h 04m

Feb 7:26 17:14 9h 48

Mar 6:20 18:10 11h 49

Apr 6:06 20:06 14h

May 5:05 20:59 15h 54m

Jun 4:36 21:36 16h 59

Jul 4:56 21:26 16h 30

Aug 5:45 20:33 14h 48

Sep 6:39 19:21 12h 41m

Oct 7:32 18;09 10h 36

Nov 7:31 16:09 8h 37

Dec 8:15 3:46 7h 31

Edited January 17, 2014 by davekm

[davekm]

Never mind. The answers here pretty much debunk my thoughts that sleep is dependent on the numbe of daylight hours. As mentioned, the shortest night is 0 mins in the arctic and they still sleep.

http://www.thenakedscientists.com/forum/index.php?topic=50105.msg429384#msg429384

Edited January 20, 2014 by davekm