SAD lamps have previously used fluorescent bulbs to create the bright light the body needs. Fluorescent bulbs are large, emit harmful UV radiation and are also expensive to run. New SAD lights are becoming available, such as the Litebook Elite, which use LEDs to create their light. This makes them much smaller, more convenient, cheaper to run and, because the light produced matches the peak wavelengths of sunlight, cut the usage time down to as little as 15 minutes.
SAD is caused by a lack of sunlight; the body uses sunlight as a trigger for several functions. The key to SAD is the production of two chemicals; serotonin and melatonin. Serotonin is produced when the body receives sunlight, and is linked with a feeling of well-being. Melatonin is the opposite; it is a hormone used to prepare the body for and during sleep. Sunlight is the body's cue to stop producing melatonin. During the winter, where sunlight is limited, the body does not receive this cue when it should, leaving you feeling down, tired and lacking energy.
SAD lamps provide light bright enough to trick the body into thinking it is daylight. During the winter, not only is there less sunlight anyway, but often the sun is yet to rise when we arrive at work and has gone down by the time we leave, meaning we receive almost no sunlight at all. SAD lamps provide enough light for the body to acknowledge that it needs to produce serotonin and stop producing melatonin, and leave you feeling your regular self.
It is worth noting that many LED light boxes use blue LEDs. It has been suggested that monochromatic blue light has negative health side effects and many studies have been conducted on this subject. Some have shown the monochromatic blue light can be toxic to human retinal structures, so it is important to ensure that any LED SAD lamp purchased uses white LEDs rather than blue, to ensure that it is safe to use and avoid this potential health hazard. Only white LEDs have been clinically proven to be both safe and effective.
For more information about Seasonal Affective Disorder, Winter Blues and light therapy, visit the newly-launched Litebook.co.uk website. It has information, advice and a wealth of clinical research, as well as a forum for SAD sufferers to interact with others with the condition and share experiences and tips with.