One thing that many modern electronic devices have in common is their use of LCD displays, which tend to produce an abundance of blue light. The problem with this is that blue light has been found to pose some serious threats to our health. It has the potential to affect your body clock, your hormone levels, and even increase your risk of cancer or heart disease.
This field of research began when Charles Czeisler published a paper in 1995, showing that our body clocks could be affected by light. Soon after, research flooded in showing that there are special light-sending cells in the retina which communicate directly with the brain’s master clock rather than the visual cortex. This biological clock affects the production of melatonin, a hormone that regulates sleep. Thus a biological mechanism explaining what was going on became clear.
The influence that blue light has on our regulation of melatonin is disturbing due to the effects that melatonin can have on the body. In one recent study, melatonin-depleted breast cancer cells injected into mice grew much faster when exposed to blue light during their night-time phase (i.e. in the 12 hours when they were sleeping, or should have been sleeping). Melatonin suppression has also been associated with obesity, diabetes and cardiovascular disease. We already know that people who work night shifts have higher levels of heart attacks and strokes, and perhaps the link has something to do with their exposure to blue light (the fluorescent lights in industrial spaces output overwhelmingly blue light)
As for the extent to which blue light can actually impact melatonin production, there are a number of studies which concluded that the highest level of suppression was found at exposure to wavelengths between 450 to 480 nanometres, which as you can see is very much in the blue range. Low-energy fluorescent bulbs and LED-based lights are the biggest culprits when it comes to blue light, so keep this in mind. You can get warmer fluorescent bulbs, but there’s not much we can do about computer screens other than avoid them late at night.
Some tips to minimise the impact of blue light on your health: