• Due to excessive bot signups along with nefarious actors we are limiting forum registration. Keep checking back for the register link to appear. Please do not send emails or have someone post to the forum asking for a signup link. Until the current climate changes we do not see a change of this policy. To join the forum you must have a compelling reason. Letting us know what skills/knowledge you will bring to the community along with the intent of your stay here will help in getting you approved.

Red Light And Circadian Cycle

J

j.

Guest
I read the interesting claim that red lights are used for night illumination because they are supposed to be safer in terms of interference on the circadian cycle.

Is there any truth to that? What are some interesting implications?

They give a bit more explanation:

The mammalian eye senses the light by the conventional rode and cone cells. However, a third light-sensing cell type has been recently identified. This third light-sensor is based on melanopsin-positive cells. While rod and cone cells respond best to white, full spectrum light, melanopsin cells only respond to a specific bandwidth of blue light, in the range of 446-477 nanometers. These cells connect and regulate brain centers responsible for circadian rhythms. Therefore, during the night, blue-light exposure might interfere with circadian rhytms facilitating the onset of depression and other metabolic derangements associated with circadian cycle see another SE question. White light contains also blue light, while red light does not. This is apparently the rationale to claim that red light is less harmful. However, no clinical evidence is available to my knowledge, and the threshold of blue light required to stimulate melanopsin receptors is probably over the common night illumination.
 

fyo

Member
Joined
Jun 9, 2013
Messages
106
short wavelength light at around 460 nm is most effective in acutely suppressing human melatonin levels... People given dark, then 2 hours of light exposure, then darkness. "There was no significant difference in sleepiness between the 550-nm light exposure and the no-light condition"... We have obtained very similar results as Brainard et al. who reported approximately 60% suppression of melatonin after 2 h of light at 460 nm. http://jcem.endojournals.org/cgi/content/full/90/3/1311

It is now well accepted that the circadian system is maximally sensitive to short-wavelength (blue) light and is quite insensitive to long-wavelength (red) light. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2744917

goggles with selective exclusion of all wavelengths less than 530 nm... All subjects demonstrated preserved melatonin levels in filtered light similar to their dim-light secretion profile. Unfiltered bright light drastically suppressed melatonin production. http://jcem.endojournals.org/cgi/content/full/90/5/2755

either blue-blocking (amber) or yellow-tinted (blocking ultraviolet only) safety glasses for 3 h prior to sleep... the amber lens group experienced significant improvement in sleep quality relative to the control group and positive affect. Mood also improved significantly relative to controls. http://www.ncbi.nlm.nih.gov/pubmed/20030543
 
J

j.

Guest
Thread starter
Great info. It seems to make sense, but I wonder what Peat thinks of it.
 

Peater

Member
Joined
Mar 26, 2014
Messages
1,250
Location
Here
This forum could not have a worse colour scheme for browsing at night then :lol: (22:00 here in UK)
 

charlie

The Law & Order Admin
Joined
Jan 4, 2012
Messages
12,296
Location
USA
Redshift or f.lux is helpful. :)
 

Mittir

Member
Joined
Feb 20, 2013
Messages
2,034
Peater said:
Charlie said:
Redshift or f.lux is helpful. :)

I use f.lux, but it doesn't turn blue to red (sadly)

Are you using "lighting at night" setting at Ember? That is 1200K
color temperature. I feel sleepy within half an hour on this setting.
I usually use 1900k setting.
 

Peater

Member
Joined
Mar 26, 2014
Messages
1,250
Location
Here
Sorry I don't know what that is, a Google search just bought up some iPhone app results
 

Mittir

Member
Joined
Feb 20, 2013
Messages
2,034
Peater said:
Sorry I don't know what that is, a Google search just bought up some iPhone app results

If you open f.lux, there is a bar next to "Done". If you click that bar you will see
"Setting at night". Then choose Ember or other setting.
 

jyb

Member
Joined
Nov 9, 2012
Messages
2,780
Location
UK
Mittir said:
If you open f.lux, there is a bar next to "Done". If you click that bar you will see
"Setting at night". Then choose Ember or other setting.

Ah, that's helpful. Stupid of me, didn't realize the default night settings is a full incandescent color!
 

paper_clips43

Member
Joined
Nov 13, 2013
Messages
258
Location
Sedona Arizona
Thanks everyone for posting about F Lux, I just download it :)
Can we just use dark room mode all the time? It seems to be much easier on my eyes.
 
J

j.

Guest
Thread starter
For what it's worth, I'm more comfortable using a real physical filter combined with flux at 3000K, than reducing Flux to 2300K or less. I don't know how to measure it but I believe the physical filter combined with flux at 3000K has a lower color temperature (i.e., is more red) than flux alone at 2700K.
 

Peater

Member
Joined
Mar 26, 2014
Messages
1,250
Location
Here
Mittir said:
Peater said:
Sorry I don't know what that is, a Google search just bought up some iPhone app results

If you open f.lux, there is a bar next to "Done". If you click that bar you will see
"Setting at night". Then choose Ember or other setting.

Done! Thanks
 

Similar threads

Top