Blue Light or White Light?

Blue Light v White Light – which to choose?

This section explains the difference between blue light technology found in some S.A.D. Light Therapy products, like the SAD Solutions BLUElight and the conventional white light found in other Light Boxes. As a short summary, blue light technology provides a safe, effective and quick treatment time and is backed up by more medical research than any other product available today. Blue light treatment has been developed in conjuction with leading US Research Universities and the National Institute for Health and has been endorsed and recommended by medical experts around the world. For more detailed information please read the information below.

Why Blue Light?

Although the light emitted by the sun appears to be white it is actually made up of the full spectrum of colours. This becomes apparent when sunlight shines through rain and it is split into the full spectrum of colours creating a rainbow. The theory behind conventional Full Spectrum (White Light) light boxes is that they effectively replicate sunshine. As a result they give the user a positive response when they are lacking sunshine (the root cause of S.A.D. and the 'Winter Blues'). What scientists have recently discovered is that specific wavelengths of blue light, that are always within sunlight, promote a positive response in light deficient patients. As a result you only need a light box that produces the specific wavelengths of light to give a therapeutic light therapy.

Blue Light Research

By isolating different wavelengths of light researchers at leading US Medical Universities and the National Institute for Health (NIH) have found that a blue wavelength alone is all that is needed to produce a positive response from sufferers of SAD and other circadian rhythm related disorders. As a result of this research, some manufacturers, like SAD Solutions have developed their own Blue Light products giving the following advantages over white light/full spectrum products:

Lower intensity of light required for treatments as you are only being subjected to a small bandwidth of light rather the full spectrum of colours

Quicker treatments times, despite being smaller products

No reported side-effects

LED technology allows for adjustable light output (most white light products are not dimmable)

Considerably Smaller products – conventional product sizes are dictated by the bulb sizes

Lighter products – weight of products are also dictated by the size of bulb and subsequent size of case

The blue wavelengths of light found in these products are always found in smaller quantities in the white light products (which usually emit the full spectrum of colours).

How light therapy works

For decades, doctors have recommended light therapy for treating mood and sleep problems. This is because part of your brain's hypothalamus (often referred to as the body clock) uses the light found in natural sunlight to regulate your body's cycles. If you struggle with sleep, mood, or energy, your body clock may not be responding properly to normal light signals. Light therapy works by simulating the light found in natural daylight to reset the circadian rhythm. By providing summertime levels of light during the winter, light therapy users can successfully alleviate the symptoms of SAD, with the result being that former sufferers can lead a normal, happier life and beat the 'Winter Blues'. In fact almost everyone can benefit from increased energy levels when using a lightbox.

Different Light Therapy Technologies

Historically only large 'full spectrum' light boxes were used to treat light deficiency disorders. However, advancements in research and technology have shown that a particular bandwidth of blue light is effective in treating such disorders. These advancements mean that Blue Light treatment lamps can now use LED's to produce the specific blue light that is most effective. As a result these lights not only offer quicker treatment times but also significantly smaller, lighter products.

Blue v White Light – The science behind the facts

Melanopsin photoreceptors must be stimulated by some blue light in order for our brains to respond to light therapy. It turns out that very bright white light works because it contains some of the necessary blue light. However, scientists have discovered that blue alone is more effective than white light. When compared to both white 10,000 lux and white LED's, blue light was twice as effective*. Additionally, by using only 8 lux of blue light, researchers were able to demonstrate the same response compared to 12,000 lux of white light. Eliminating these unnecessary wavelengths increases effectiveness and also significantly reduces overall intensity.

Why isn't white as effective?

Most 10,000 lux products contain much more blue light, so why aren't they as effective as low-level blue light? Part of the answer may be that high-intensity white light may over-stimulate the eye's photoreceptors, making it more difficult for melanopsin to respond. Some researchers believe that other wavelengths create 'spectral opponency' and cancel out the effectiveness of the blue spectrum. It seems obvious though, that eliminating unnecessary wavelengths lowers the needed amount of blue light, while still being more effective than white

* Wright H R et al. Differential effects of light wavelength in phase advancing the melatonin rhythm. J. Pineal Res. 2004; 36: 140-144 Lockley S. et al. High Sensitivity Of The Human Circadian Melatonin Rhythm To Resetting By Short Wavelength Light. The Journal of Clinical Endocrinology & Metabolism 2003; 88(9):4502–4505
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