IceCream Wrote:i haven't tried it yet, but i don't think blue light therapy is a placebo at all.
There is a part of the brain called the suprachiasmatic nuclei http://en.wikipedia.org/wiki/Suprachiasmatic_nucleus which entrains the body to the 24 hour circadian rhythm. It has been shown that changing or witholding light sources changes the circadian rhythm in other mammals so that it no longer runs in a 24 hour cycle. Many of the neurons in the SCN are sensitive to light. It is highly likely that the cycle of light and darkness entrains our sleep and wake cycles to the 24 hour day.
Different genes determine how sensitive to light the SCN is in different people (um, sort of). If your SCN isn't particularly sensitive to light, you may have some problems sleeping if you don't go out in the early morning enough, or when light is weaker, such as in winter. Using a blue light can help with this. However, the opposite is also true, if you're using a lot of bright lights at night, such as on your computer, it can delay your sleep.
Cutting out caffeine after the afternoon sleepiness also helps!!!
It's true that your circadian rhythm is affected by light--I wouldn't doubt that at all. The thing is that just because light affects circadian rhythm it does not mean that this device actually does anything.
If you follow medical studies at all, you'll see this kind of pattern: Drug companies know from studies about certain physical properties. Then they try to make a drug using the understanding of those physical properties. When they actually do a placebo controlled study testing these drugs, they find that the drugs don't work at all the vast majority of the time!
An example being the whole antioxidant thing. Free radicals seem to be bad, because they damage your cells and cell damage causes cancer. So there were studies done to establish the physical properties of free radicals. Studies also showed that antioxidants remove free radicals. This should result in less cell damage, right? So if we just give people more antioxidants cancer rates should go down.
So, then they did long term double blind studies in which the patients got antioxidant suppliments, and the control group got sugar pills. The result? People who were taking the antioxidant suppliments had a higher mortality rate--more of them died and faster. One of the major studies was even stopped early because it was considered unethical.
So it may SEEM like it will work based on what we understand about human physiology, but then it turns out otherwise.
What you would need to prove that this blue light thing works is a study that actually compares it to a placebo (maybe just a cheap 10 dollar dim blue screen), and you would need the study to explain how the people in the study were chosen, how many people there were, how the placebo was set up, how the results were blinded or double-blinded, etc. And you would need that to be published publically to be sure that the company isn't doing something funky. It says there were 'clinical trials', but I guarantee you that they weren't published publically--I smell bullshit.
So, in short, the fact that light is related to circadian rhythm doesn't mean that any given product improves sleep cycles.
Edit: Posted before I noticed the Wikipedia light therapy post from Ice Cream, which is a little harder to respond to.
Edited: 2011-01-03, 11:32 pm
